- Email: [email protected]
Nutritional values of potato slices added with rosemary essential oil cooked in sous vide bags
Author’s Accepted Manuscript Nutritional values of potato slices added with rosemary essential oil cooked in sous vide bags Luana Amoroso, Muratore
Valeria
Rizzo,
Giuseppe
www.elsevier.com
PII: DOI: Reference:
S1878-450X(18)30129-X https://doi.org/10.1016/j.ijgfs.2018.11.007 IJGFS128
To appear in: International Journal of Gastronomy and Food Science Received date: 31 August 2018 Revised date: 23 November 2018 Accepted date: 23 November 2018 Cite this article as: Luana Amoroso, Valeria Rizzo and Giuseppe Muratore, Nutritional values of potato slices added with rosemary essential oil cooked in sous vide bags, International Journal of Gastronomy and Food Science, https://doi.org/10.1016/j.ijgfs.2018.11.007 This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting galley proof before it is published in its final citable form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
Nutritional values of potato slices added with rosemary essential oil cooked in sous vide bags. Luana Amoroso, Valeria Rizzo*, Giuseppe Muratore
Di3A – Dipartimento di Agricoltura, Alimentazione e Ambiente, University of Catania, Via Santa Sofia, 100, 95123 Catania, Italy *Corresponding author. E-mail address: [email protected] (V. Rizzo)
ABSTRACT The sous vide packaging method, in association with rosemary essential oil (REO), was confirmed as a good strategy for the quality preservation of sliced potatoes over refrigerated storage until 11 days. Looking at vegetables as sources of phytochemicals together with the benefits of sous vide cooking method validated by several studies, taking into account the increasing interest in early crop variety and their nutritional value and considering that potatoes must be cooked to be eaten, the potato slices treated with peanut oil and with the addition of REO were monitored on ascorbic acid, total polyphenols content and antioxidant activity. Results demonstrated that the presence of REO have no “a direct” effect on the nutritional content of cooked samples, but it was probably linked with the protection of such compounds. The ascorbic acid (AsAc) was better preserved (24.7 ± 4.06 mg/100g DM) and values were kept nearest to the raw tubers having moderate loss with a maximum of 20% in Erika. Total polyphenol content (TPC) was well maintained after cooking, ranging from 337 to 257 mg/100g DM, of course the varieties with the highest content were able to save a high amount of the compound studied, and the antioxidant activity (AA) calculated showed a loss mean value of 48% among cultivars. Hence, we can conclude that potato slices treated with REO, packaged in sous vide bags and cooked at 105 ± 5 °C for 15 minutes, retain nearly all the nutritive compounds considered in our study. The most suitable cultivar identified to be stored as
fresh cut potato slices with the addition of REO in sous vide bags and then cooked, was Elodie: it was able to save the highest nutritive values among cultivars studied holding AsAc and TPC content as well as the smaller reduction in AA from the fresh material.
Keywords: Sous vide; cooked potato; rosemary essential oil; nutritional values, phenols; antioxidants
1. Introduction Sous vide is the French word for ‘‘under vacuum’’ and sous vide cooking is defined as ‘‘raw materials or raw materials with intermediate foods that are cooked under controlled conditions of temperature and time inside heat-stable vacuumized pouches’’ (Schellekens, 1996). As reported by Baldwin D.E. (2012) sous vide is a method of cooking in vacuumized plastic pouches at precisely controlled temperatures. The opportunity to set precise temperature control gives more choice over doneness and texture than traditional cooking methods, improving shelf-life and with the opportunity to enhance taste and nutritional values. The benefits of sous vide are validated by several studies (Tudela et al., 2002; Baldwin, 2012; Fabbri and Crosby, 2016). Considering how vegetables are rich sources of phytochemicals, in addition to other components, that may act synergistically with phytochemicals that contribute to the nutritional quality and health benefit of such food commodities (Albishi et al., 2013) this cooking method become particularly interesting. A number of essential oils (EOs) and several of their individual components exhibit antibacterial activity in vitro and, to a lesser extent, in foods, so they are used for the inhibition of growth and reduction in numbers of the more serious food borne pathogens (Burt, 2004). The delay of spoilage and improvement of organoleptic qualities in vacuum packed products may be interesting from a commercial point of view, allowing for the synergism and antagonism between components of EOs and food constituents.
Potato (Solanum tuberosum) is a major staple food for humans and the fourth largest crop that is grown worldwide after rice, wheat, and maize (Singh and Saldana, 2011), the annual global production of potato and the million hectares dedicated to its production encourage researchers to analyze the different nutritional and healthy aspects. An increasing interest is in early crop varieties and their nutritional value, to increment the knowledge about the important phytochemicals contained in this most consumed tuber and its processing by-products. Almost all information about the ascorbic acid (AsAc) concentration of potatoes in freshly harvested and stored potatoes in raw and cooked tubers relates to improved commercial varieties and there is scant information about the nutrient concentration of potato genetic resources. However, several authors studied phenolic content, reduction in the quantities of ascorbic acid during cooking and antioxidant activities of different potato varieties as affected by environment and their processing by-products (Albishi et al., 2013; Burgos et al., 2009), as well as they have been described considerable losses that vary widely according to cooking method (Augustin et al., 1978; Leskova´ et al., 2006; Suarez et al., 2004) and with storage time (Rivero et al., 2003; Mishra, 1985; Zee et al., 1991). Polyphenols are recognized as the most abundant antioxidants in the human diet (Manach et al., 2004), able to prevent or control the formation of free radicals with deleterious health effects and are therefore important in disease risk reduction (Shahidi, 2000). After previous studies on the raw tuber (Lombardo et al., 2013, 2017) and on the effect of sous vide packaging on storage quality of fresh-cut potato (Rizzo et al., 2018), the objective of the present research was to determine the nutritional values of potato slices of six different cultivars cooked in sous vide bags after 4, 7 and 11 days of cold storage. Considering that potatoes must be cooked to be eaten, the potato slices treated with peanut oil and with the addition of rosemary essential oil (REO) were monitored on ascorbic acid, total polyphenols content and antioxidant activities expressed as percentage inhibition
of DPPH radical to determine the cultivar having the highest nutritional values after these processing.
2. Materials and Methods 2.1. Sample preparation, packaging and cooking information The processing was carried out on potato tubers of six different cultivars: Arinda, Elodie, Erika, Fontane, Marabel and Ranomi. All of them present yellow skin and pulp. The cultivation system, irrigation, agronomic information to the harvest and qualitative traits of selected tubers are provided by Rizzo et al. (2018). Marketable tubers were directly transported to the laboratory of the Di3A (Department of Agriculture, Food and Environment) where all varieties were prepared as described in Rizzo et al. (2018). Briefly potatoes were sanitized in solution of sodium hypochlorite at 2%, were peeled and cut, using a manual slicer, in 1 cm-thick slices, then after a further washing by immersion (2 min) in distilled water slices were manually centrifuged. Afterwards about 10 kg of sliced potatoes were used, half of which was uniformly dipped in a mixture of 150 mL of peanut seed oil added with 0.5% (v/v) rosemary essential oil (REO), while the remaining half was dipped into peanut oil and used as control. About 200 g of potatoes, corresponding to an average of 6-8 slices, were placed in sous vide cooking bags, 20×30 cm, by ORVED S.p.A. (Musile di Piave, VE, Italy). The final 50 bags (25 dipped in peanut seed oil + REO, and 25 as control) were vacuumsealed employing a vacuum packaging machine (DELTA 30, FIMA srl, Ariano Irpino, AV, Italy). Sous vide bags sold by ORVED S.p.A. were composed using a bi-layer film made of: bi-oriented polyamide (OPA, 15 μm thick, 17.2 g m-2) for the side not in contact with the product; twocomponent polyurethane (3 g m-2) as adhesive; cast polypropylene (CPP, 60 μm thick, 54 g m-2) for the side in contact with the product, designed for vacuum storage and sous vide cooking up to 121 °C for 30 minutes. All samples were stored under refrigerated conditions at +4 ± 2 °C until cooking; a small portion of each sample was cooked, inside own sous vide bag, by boiling for 15 min at 105 ± 5°C. Finally, cooked samples were kept at -80 ± 5 °C until analysis.
All chemical analyzes were performed in triplicate. All the reagents and solvents for the chemical determinations were purchased from Sigma-Aldrich (Milano, Italy) and were of HPLC grade. Bidistilled water was used throughout this analytical trial.
2.2. Ascorbic Acid content Ascorbic acid content (AsAc) was evaluated considering the ability of AsAc to reduce the dye 2,6dichloroindophenol following the spectrophotometric method used by Burgos et al. (2009) with slightly modifications. Briefly, 15 g of each defrosted sample was extracted with an oxalic acid and acetone solution (0.4 and 20%, respectively) by homogenizing at 4000 rpm for 15 min, filtered through filter paper Whatman n.4 and brought to 100 mL with the same extracting solution. 0.5 milliliter of the extract was reacted with 2 mL of 2,6-dichloroindophenol (prepared according to AOAC official method (2005) and diluted 1:5) during 1 min and read at 520 nm on a spectrophotometer (UV-2401 Shimadzu Co., Japan). Results were expressed as mg on 100 g of fresh weight (FW). Dehydroascorbic acid (DHAA) is present in very low amount in potatoes (Burgos et
al., 2009) so we do not evaluate its concentration. The AsAc concentration was made through comparison with a standard curve of L-Ascorbic acid pure commercial standard (Carlo Erba Reagenti, Milan, Italy).
2.3. Total polyphenol content For the extraction of total polyphenols (TP), we followed the procedure as reported by Lombardo et al., (2013). 2.5 g of defrosted material were treated with 50 mL of ethanol 80% (v/ v), blended for 2 min, stirred at room temperature for 1 h and then centrifuged at 4000 rpm during 15 min. The filtrate (through Whatman No. 4 filter paper) was stored at -80 ± 5 °C until analysis was performed. The Folin-Ciocalteu assay (Singleton and Rossi, 1965) was used to quantify the TP content (TPC). The absorbance was measured at 760 nm using a spectrophotometer (UV-2401 Shimadzu Co., Japan). The TPC was determined on the basis of a standard calibration curve generated with known
amounts of gallic acid (Sigma, Milan, Italy), and results expressed as mg on 100 g of fresh weight (FW).
2.4. Antioxidant activity The antioxidant activity (AA) of the extracts obtained for TPC determination was evaluated as percentage inhibition of DPPH radical (Brand-Williams et al., 1995). An aliquot (0.1 mL) of each extract was added to 3.9 mL of freshly prepared methanolic solution containing 0.24 g L-1 DPPH, and held in the dark for 30 min at room temperature. Then, the absorbance was measured at 515 nm. The percentage inhibition of DPPH was obtained by the following equation: [(AC(0) − AS(t)/AC(0)] × 100, where AC(0) is the absorbance of the blank control at the beginning of the experiment assay, and AS(t) the sample absorbance after 30 min.
2.5. Statistic Bartlett’s test was used to test the homogeneity of variances, following which the data were subjected to a three-way analysis of variance (ANOVA), using CoStat release 6.311 (CoHort Software, Monterey, CA, USA), to determine the effects of “cultivar (6) x treatments (2) x storage time (4)”. Means were compared using least significance difference (LSD) test (P≤0.05).
3. Results and discussion In Table 1 are reported the effect of the different cultivar, storage time, dipping treatment and their interactions on the AsAC, TPC and AA on sous vide cooked potato slices. Results were expressed in mg/100 g of fresh weight (FW) and considering the dry matter content of the individual cultivars, determined on the raw material (Lombardo et al., 2017), concentrations were also expressed in mg/100 g of dry matter (DM). The different cultivars analyzed showed the highest significance for TPC and AA (P<0.001) while it was of P<0.01 for AsAc. As well as the six cultivars, also the storage time was significant in our testing, differently with nutritional components studied after
sous vide cooking. After the analysis of the main effects, as not surprising consequence, only the interaction “cultivar x storage” was significant (P<0.001) for all nutritional traits, while the interaction “cultivar (C) x treatment (T)” was significant only for the value of AA. The sous vide cooking applied for our experiments is near to the boiling applied by Burgos et al., (2009) because bags were placed in a stainless steel pot and cooked over uniform high temperature almost 100 °C but with the difference that the time was shorter, around 13–15 min, so in the middle between time reported for boiling and microwave cooking in the same cited paper (Burgos et al., 2009). Vegetables are a rich source of vitamins and minerals which are lost when they are boiled, steamed, or microwaved while sous vide cooked vegetables, in comparison, retain nearly all their nutritive value because sous vide vegetables leave the cell walls mostly intact (Baldwin, 2012). Considering the dipping treatment (Table 1), the presence of REO had no significant effect on the nutritional characteristic considered in cooked samples, in the same way also interactions between other factors with treatment have no significant differences with the only exception, as said, for the interaction “C x T” for AA. Moreover, from a previous experience where the synergistic use of REO and vacuum packaging, combined with refrigerated storage, had positive effects on the quality preservation of minimally processed potatoes (Rizzo et al., 2018), REO treatment effectiveness was probably much linked to dipping solution, explicating its effect before cooking processing. As reported in literature, generally EO’s have demonstrated antibacterial activity against food borne pathogens, and on the phenolic components, which are most active and appear to be active principally as membrane permeabilisers (Burt, 2004). The AsAc content was slightly low in all samples, ranging from 4.9 to 3.2 mg/100g FW: taking into account that this compound is commonly considered heating sensitive, Elodie cultivar kept the highest AsAc content while Erika kept the lowest (Table 1). The influence of storage was significant different among the cultivars but is explained in a small range of values and the reduction after cooking was confirmed also by Burgos et al. (2009), however it is well known that AsAc is sensitive to air, heat and water, and can easily be destroyed by prolonged storage (Zee et al,
1991). Previously reported values of the AsAc of raw tubers of the same cultivars, on a DM basis ranged from 21.7 to 28.5 mg/100g (Rizzo et al., 2018), while AsAc concentration of sous vide cooked slices were slightly higher than those reported by Burgos et al. (2009) in three cooking methods studied (boiling, baking and microwaving). In particular, considering how the retention values of boiled tubers ranged from 54 to 97%, we can affirm that sous vide cooking probably thanks to the additional treatment with REO, better preserve the AsAc keeping values nearest to the raw tubers with moderate loss to a maximum of 20% in Erika. The AsAc content seems increasing during storage from 2.7 to 4.3 mg/100 g FW after 11 days with a maximum of 5 mg/100 g FW in the sampling carried out after 4 days of storage, probably this path could be explained considering the high variability of the AsAc content available in tested cultivars as reported by Lombardo et al. (2017). TPC is well preserved after cooking, of course the varieties with the highest content are able to save a high amount of the compound studied; Elodie showed the highest TPC followed by Ranomi while the lowest was observed in Arinda cultivar. TPC on raw tubers measured from 2.68 to 4.23 g kg-1 DM (Rizzo et al., 2018), and the concentration after sous vide cooking was from 337 to 257 mg/100 g DM; the results were in line with those reported by Tierno et al. (2015) whom evaluated the effect of boiling on total phenolic values ranged from 142 to 359 mg GAE 100 g-1 DW in raw tubers and confirmed a decreasing for all cultivars studied when the potatoes were boiled from 78.0 to 221 mg GAE 100 g-1 DW. After boiling processing, from 45 to 74% of the TPC was retained for all cultivars, with the exception of the pale yellow-fleshed in which the retention was very much higher (93.5%) as well as in our samples (all yellow-fleshed cultivars) were the retention was from 75 to 96%. TPC values in sous vide cooked samples were consistent with data from raw tuber (Lombardo et al., 2017; Rizzo et al., 2018) underlining the variability inside the same cultivar, but also the protection probably extended by REO. Sure enough the highest values of AsAc and TPC reported during storage, respect to the initial content detected, should be linked to such protections from REO on the phenolic components. From literature there is a clear evidence that the total amount of
phenolics in potato varies significantly among different varieties (Brandl and Herrmann, 1984), as it was also observed for our varieties in the past paper (Rizzo et al., 2018; Lombardo et al., 2017), while this consideration is probably weaker for the same cultivars after sous vide cooking. Significant difference among varieties may be attributed to genotypes and harvest location which influence the accumulation of phenolic compounds, but those aspects are perhaps misplaced with cooking processing. Also, the AA was reduced in sous vide cooked potato slices, with a loss mean value of 48% among cultivars, Fontane showed the highest AA value and Erika the lowest whereas considering the reduction from initial AA on the raw material Elodie kept the highest AA content. In samples cooked after different storage time, was noticed an increasing in AA, as previously reported by Tudela et al. (2002); total flavonoids were induced by the fresh cut process in potatoes and their loss was pronounced during cooking differently among the various cooking practices. Some authors did not find any correlation between the TPC and AA on many plant extracts, but for others, AA in fruit and vegetables was mainly attributed to phenol content, and in some case together with AsAc Cabezas-Serrano et al. (2009). Probably in the present study, as well as reported by Cabezas-Serrano et al. (2009), AA was correlated more with AsAc than with TP. This can be explained by the fact that antioxidant capacity is mainly provided by ascorbic acid, while phenolic contribution to oxidative reaction is more decisive than its antioxidant role. Results of this work confirmed the extreme differences existing among potato varieties in terms of post-cutting performances, and the need to extend the screening to other varieties, in order to have more raw material available for processing according to the season availability. In addition, when the same performances are obtained, the choice may be directed to those varieties with higher nutritional value.
4. Conclusion Looking at the positive results obtained in a past experience, with the synergistic use of REO and vacuum packaging, combined with refrigerated storage on the quality preservation of minimally processed potatoes we hoped to detect such positive effect also after cooking in sous vide on nutritional compounds. Ascorbic Acid, total phenols and antioxidant activity were slightly reduced so well preserved after sous vide cooking. A good result was observed on AsAc, commonly considered heating sensitive, after sous vide cooking it was higher than concentrations reported in literature after different cooking methods, suggesting a good effect of cooking in vacuumized plastic pouches at precisely controlled temperatures. TPC was well preserved after cooking especially in our yellow-fleshed cultivars, and the AA showed a loss mean value of 48% among cultivars. Although the most suitable cultivars identified to be processed in fresh cut potato slices with the addition of REO to be store and then cooked in sous vide bags were Fontane and Marabel (Rizzo et al., 2018), we can assess that the cultivar with the highest nutritive values among cultivars studied is Elodie, with positive results also from the two cultivars previously cited. Nutritional characteristics pointed out in this experiment, on potato slices treated with REO and cooked in sous vide pouches, were kept by the samples, suggesting as more study are require before EO’s and sous vide cooking bags can be reliably used in commercial applications, as well as major investigations should be done on interaction with AsAc in food matrix, the use of EOs in consumer goods is expected to increase in the future due to the rise of ‘green consumerism’ improving nutritive quality for final consumers.
Acknowledgements The authors thank Prof. Giovanni Mauromicale (Catania University) for having provided the tuber material and Dr. Ph D. Stefania Toscano (Catania University) for advice on statistical analyses.
Funding: This work was financially supported by Project “Utilizzo integrato di approcci tecnologici innovativi per migliorare la shelf-life e preservare le proprietà nutrizionali di prodotti agroalimentari (shelf-life)” (PON 02_00451-3361909). Interests statement Conflicts of Interest: The authors declare no conflict of interest.
References Albishi, T., John, J.A., Al-Khalifa, A.S., Shahidi, F., 2013. Phenolic content and antioxidant activities of selected potato varieties and their processing by-products. J. Functional Foods, 5, 590-600. https://doi.org/10.1016/j.jff.2012.11.019. AOAC Official Method 967.21. (2005). Ascorbic acid in vitamin preparations and juices. 2,6dichloroindophenol titrimetric method, 45.1.14. , J. AOAC Int., 45, 22-23 Augustin, J., Johnson, S.R., Teitzel, C., True, R.H., Hogan, J.M., Toma, R.B., Shaw, R.L., Deutsch, R.M., 1978. Changes in the nutrient composition of potatoes during home preparation. II. Vitamins. Am. Potato J. 55, 653–662. https://doi.org/10.1007/BF02852138. Baldwin, D.E., 2012. Sous vide cooking: A review. Int. J. Gastronomy and Food Science, 1, 15-30. https://doi.org/10.1016/j.ijgfs.2011.11.002 Brandl, W., Herrmann, K., 1984. Occurrence of chlorogenic acid in potatoes. Zeitschriftfur Lebensmittel-Untersuchung
und
-
Forschung,
178,
192–194.
https://doi.org/10.1007/BF01043358. Brand-Williams, W., Cuvelier, M. E., Berset, C., 1995. Use of a free radical method to evaluate antioxidant
activity.
Lebensmittel-Wissenschaft
https://doi.org/10.1016/S0023-6438(95)80008-5.
und
-Technologie,
28,
25–30.
Burgos, G., Auqui, S., Amoros, W., Salas, E., Bonierbale, M., 2009. Ascorbic acid concentration of native Andean potato varieties as affected by environment, cooking and storage. J. Food Comp. Anal. 22, 533–538. https://doi.org/10.1016/j.jfca.2008.05.013. Burt S. (2004). Essential oils: their antibacterial properties and potential applications in foods – a review. Int. J. Food Microb. 94, 223–253. Cabezas-Serrano, A. B., Amodio, M. L., Cornacchia, R., Rinaldi, R., & Colelli, G. (2009). Suitability of five different potato cultivars (Solanum tuberosum L.) to be processed as fresh-cut products. Post. Harvest Biol and Technology, 53, 138–144. Fabbri, A.D.T., Crosby G.A., 2016. A review of the impact of preparation and cooking on the nutritional quality of vegetables and legumes. Int. J. Gastronomy and Food Science, 3, 2-11. https://doi.org/10.1016/j.ijgfs.2015.11.001. Hesam, F., Balali, G.R., Tehrani, R.T., 2012. Evaluation of antioxidant activity of three common potato (Solanum tuberosum) cultivars in Iran. Avicenna J Phytomed., 2(2), 79–85. https://doi.org/10.22038/ajp.2012.36. Lešková, E., Kubíková, J., Kováčiková, E., Košická, M., Porubská, J., Holčíková, K., 2006. Vitamin losses: Retention during heat treatment and continual changes expressed by mathematical
models.
J.
Food
Comp.
Anal.
19
(4),
252–276.
https://doi.org/10.1016/j.jfca.2005.04.014. Lombardo, S., Pandino, G., Mauromicale, G., 2013. The influence of growing environment on the antioxidant and mineral content of “early” crop potato. J. Food Comp. Anal., 32 (1), 28-35. https://doi.org/10.1016/j.jfca.2013.08.003. Lombardo, S., Pandino, G., Mauromicale, G., 2017. The effect on tuber quality of an organic versus a conventional cultivation system in the early crop potato. J. Food Comp. Anal., 62, 189-196. http://doi.org/10.1016/j.jfca.2017.05.014.
Manach, C., Scalbert, A., Morand, C., Rémésy C., Jiménez L., 2004. Polyphenols: Food sources and
bioavailability.
Am.
J.
Clinical
Nutrition,
79
(5),
727–747.
https://doi.org/10.1093/ajcn/79.5.727. Mishra, J.B., 1985. Effect of conditions of storage on ascorbic acid content and sprouting of tubers of some Indian potato varieties. J. Indian Potato Assoc. 12 (3&4), 158–164. Rivero, R.C., Rodríguez, E.R., Romero, C.D., 2003. Effects of current storage conditions on nutrient retention in several varieties of potatoes from Tenerife. J. Food Chem. 80, 445–450. https://doi.org/10.1016/S0308-8146(02)00281-9. Rizzo, V., Amoroso, L., Licciardello, F., Mazzaglia, A., Muratore, G., Restuccia, C., Lombardo, S., Pandino, G., Strano, M. G., Mauromicale, G., 2018. The effect of sous vide packaging with rosemary essential oil on storage quality of fresh-cut potato. LWT - Food Science and Technology, 94, 111–118. https://doi.org/10.1016/j.lwt.2018.04.033. Schellekens, M., 1996. New research issues in sous-vide cooking. Trends in Food Science and Technology 7 (8), 256–262. https://doi.org/10.1016/0924-2244(96)10027-3. Shahidi, F.(2000). Antioxidants in food and food antioxidants. Nahrung – Food,44, 158–163. Singh, P.P., Saldaña, M.D.A., 2011. Subcritical water extraction of phenolic compounds from potato peel. Food Res. Int., 44 (8), 2452-2458. https://doi.org/10.1016/j.foodres.2011.02.006. Singleton, V.L., Rossi, J.A., 1965. Colorimetry of total phenolics with phosphomolybdic phosphotungstic acid reagents. Am J Enol Vitic. 16, 144–158. Suárez, H.P., Rodríguez, R.E.M., Díaz, R.C., 2004. Cambios en el valor nutritivo de patatas durante distintos
tratamientos
culinarios.
Cienc.
Tecnol.
Aliment.
4
(4),
257–261.
https://doi.org/10.1080/11358120409487768. Tierno, R., Hornero-Méndez, D., Gallardo-Guerrero, L., López-Pardo, R., Ruiz de Galarreta, J.I,. 2015. Effect of boiling on the total phenolic, anthocyanin and carotenoid concentrations of potato tubers from selected cultivars and introgressed breeding lines from native potato species. J. Food Comp. Anal. https://doi.org/10.1016/j.jfca.2015.01.013
Tudela, J.A., Cantos, E., Espín, J.C., Tomás-Barberán, F.A., Gil, M.I., 2002. Induction of antioxidant flavonol biosynthesis in fresh-cut potatoes. Effect of domestic cooking. J. Agric. Food Chem., 50 (21), 5925-5931. https://doi.org/10.1021/jf020330y. Zee, J.A., Carmichael, L., Codère, D., Poirier, D., Fournier, M., 1991. Effect of storage conditions on the stability of vitamin C in various fruits and vegetables produced and consumed in Quebec. J. Food Comp. Anal. 4 (1), 77–86. https://doi.org/10.1016/0889-1575(91)90050-G.
Table 1. Mean effects of six cultivar (C) and two dipping treatments (T) during storage time (S) on ascorbic acid, total polyphenol content and antioxidant activity on sous vide cooked potato slices. Dipping treatmenta Cultivar (C) Arinda Elodie Erika Fontane Marabel Ranomi A B Storage (d) 0 4 7 11
AsAc (mg/100 g FW)
AsAc (mg/100 g DM)
TPC (mg/100 g FW)
TPC (mg/100 g DM)
AA (% DPPH inhibition)
4.2±0.27ab 4.9±0.20a 3.2±0.28c 4.1±0.19b 4.0±0.20bc 3.8±0.25bc
25.32±15.40b 30.42±12.51a 18.00±15.41c 23.21±10.47b 26.31±12.97b 24.83±16.02b
45.3±0.80d 53.3±0.81a 50.3±0.58ab 46.5±0.58cd 49.3±0.78bc 51.9±0.79ab
257.4±154.38b 332.9±106.77a 276.5±116.51a 259.6±125.02b 320.4±108,66a 336.8±113,57a
17.89±4.46bc 17.72±5.83bc 16.50±7.02c 21.54±4.06a 17.94±2.75bc 18.76±4.11b
4.1±0.23 4.0±0.24
25.12±14.24 24.22±14.02
49.3±0.68 49.6±0.86
296.2±155.02 298.3±154.78
18.23±5.59 18.55±4.47
2.7±0.23c 5.0±0.13a 4.1±0.29b 4.3±0.20ab
18.25±14.05c 29.67±13.79a 24.57±14.42b 26.23±13.74b
52.9±0.95a 48.8±0.83b 49.2±0.60b 46.8±0.51b
318.7±157.39a 293.8±172.76b 294.8±126.56b 281.8±127.89b
14.58±6.67c 21.39±4.37a 19.42±2.89b 18.19±2.51b
time
Main effect Cultivar (C) Dipping treatmenta (T) Storage time (S) Interaction CxT CxS TxS
**
***
***
NS
NS
NS
***
**
***
NS *** NS
NS *** NS
*** *** NS
Note: AsAC: ascorbic acid content; TPC: total polyphenol content; AA: antioxidant activity; ***, ** and *
indicate significant at P <0.001, P<0.01 and P<0.05, and NS, not significant. Different letters
indicate statistical differences for P ≤ 0.05. a
A: dipping in peanut oil; B: dipping in peanut oil and rosemary essential oil.
Valeria
Rizzo,
Giuseppe
www.elsevier.com
PII: DOI: Reference:
S1878-450X(18)30129-X https://doi.org/10.1016/j.ijgfs.2018.11.007 IJGFS128
To appear in: International Journal of Gastronomy and Food Science Received date: 31 August 2018 Revised date: 23 November 2018 Accepted date: 23 November 2018 Cite this article as: Luana Amoroso, Valeria Rizzo and Giuseppe Muratore, Nutritional values of potato slices added with rosemary essential oil cooked in sous vide bags, International Journal of Gastronomy and Food Science, https://doi.org/10.1016/j.ijgfs.2018.11.007 This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting galley proof before it is published in its final citable form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
Nutritional values of potato slices added with rosemary essential oil cooked in sous vide bags. Luana Amoroso, Valeria Rizzo*, Giuseppe Muratore
Di3A – Dipartimento di Agricoltura, Alimentazione e Ambiente, University of Catania, Via Santa Sofia, 100, 95123 Catania, Italy *Corresponding author. E-mail address: [email protected] (V. Rizzo)
ABSTRACT The sous vide packaging method, in association with rosemary essential oil (REO), was confirmed as a good strategy for the quality preservation of sliced potatoes over refrigerated storage until 11 days. Looking at vegetables as sources of phytochemicals together with the benefits of sous vide cooking method validated by several studies, taking into account the increasing interest in early crop variety and their nutritional value and considering that potatoes must be cooked to be eaten, the potato slices treated with peanut oil and with the addition of REO were monitored on ascorbic acid, total polyphenols content and antioxidant activity. Results demonstrated that the presence of REO have no “a direct” effect on the nutritional content of cooked samples, but it was probably linked with the protection of such compounds. The ascorbic acid (AsAc) was better preserved (24.7 ± 4.06 mg/100g DM) and values were kept nearest to the raw tubers having moderate loss with a maximum of 20% in Erika. Total polyphenol content (TPC) was well maintained after cooking, ranging from 337 to 257 mg/100g DM, of course the varieties with the highest content were able to save a high amount of the compound studied, and the antioxidant activity (AA) calculated showed a loss mean value of 48% among cultivars. Hence, we can conclude that potato slices treated with REO, packaged in sous vide bags and cooked at 105 ± 5 °C for 15 minutes, retain nearly all the nutritive compounds considered in our study. The most suitable cultivar identified to be stored as
fresh cut potato slices with the addition of REO in sous vide bags and then cooked, was Elodie: it was able to save the highest nutritive values among cultivars studied holding AsAc and TPC content as well as the smaller reduction in AA from the fresh material.
Keywords: Sous vide; cooked potato; rosemary essential oil; nutritional values, phenols; antioxidants
1. Introduction Sous vide is the French word for ‘‘under vacuum’’ and sous vide cooking is defined as ‘‘raw materials or raw materials with intermediate foods that are cooked under controlled conditions of temperature and time inside heat-stable vacuumized pouches’’ (Schellekens, 1996). As reported by Baldwin D.E. (2012) sous vide is a method of cooking in vacuumized plastic pouches at precisely controlled temperatures. The opportunity to set precise temperature control gives more choice over doneness and texture than traditional cooking methods, improving shelf-life and with the opportunity to enhance taste and nutritional values. The benefits of sous vide are validated by several studies (Tudela et al., 2002; Baldwin, 2012; Fabbri and Crosby, 2016). Considering how vegetables are rich sources of phytochemicals, in addition to other components, that may act synergistically with phytochemicals that contribute to the nutritional quality and health benefit of such food commodities (Albishi et al., 2013) this cooking method become particularly interesting. A number of essential oils (EOs) and several of their individual components exhibit antibacterial activity in vitro and, to a lesser extent, in foods, so they are used for the inhibition of growth and reduction in numbers of the more serious food borne pathogens (Burt, 2004). The delay of spoilage and improvement of organoleptic qualities in vacuum packed products may be interesting from a commercial point of view, allowing for the synergism and antagonism between components of EOs and food constituents.
Potato (Solanum tuberosum) is a major staple food for humans and the fourth largest crop that is grown worldwide after rice, wheat, and maize (Singh and Saldana, 2011), the annual global production of potato and the million hectares dedicated to its production encourage researchers to analyze the different nutritional and healthy aspects. An increasing interest is in early crop varieties and their nutritional value, to increment the knowledge about the important phytochemicals contained in this most consumed tuber and its processing by-products. Almost all information about the ascorbic acid (AsAc) concentration of potatoes in freshly harvested and stored potatoes in raw and cooked tubers relates to improved commercial varieties and there is scant information about the nutrient concentration of potato genetic resources. However, several authors studied phenolic content, reduction in the quantities of ascorbic acid during cooking and antioxidant activities of different potato varieties as affected by environment and their processing by-products (Albishi et al., 2013; Burgos et al., 2009), as well as they have been described considerable losses that vary widely according to cooking method (Augustin et al., 1978; Leskova´ et al., 2006; Suarez et al., 2004) and with storage time (Rivero et al., 2003; Mishra, 1985; Zee et al., 1991). Polyphenols are recognized as the most abundant antioxidants in the human diet (Manach et al., 2004), able to prevent or control the formation of free radicals with deleterious health effects and are therefore important in disease risk reduction (Shahidi, 2000). After previous studies on the raw tuber (Lombardo et al., 2013, 2017) and on the effect of sous vide packaging on storage quality of fresh-cut potato (Rizzo et al., 2018), the objective of the present research was to determine the nutritional values of potato slices of six different cultivars cooked in sous vide bags after 4, 7 and 11 days of cold storage. Considering that potatoes must be cooked to be eaten, the potato slices treated with peanut oil and with the addition of rosemary essential oil (REO) were monitored on ascorbic acid, total polyphenols content and antioxidant activities expressed as percentage inhibition
of DPPH radical to determine the cultivar having the highest nutritional values after these processing.
2. Materials and Methods 2.1. Sample preparation, packaging and cooking information The processing was carried out on potato tubers of six different cultivars: Arinda, Elodie, Erika, Fontane, Marabel and Ranomi. All of them present yellow skin and pulp. The cultivation system, irrigation, agronomic information to the harvest and qualitative traits of selected tubers are provided by Rizzo et al. (2018). Marketable tubers were directly transported to the laboratory of the Di3A (Department of Agriculture, Food and Environment) where all varieties were prepared as described in Rizzo et al. (2018). Briefly potatoes were sanitized in solution of sodium hypochlorite at 2%, were peeled and cut, using a manual slicer, in 1 cm-thick slices, then after a further washing by immersion (2 min) in distilled water slices were manually centrifuged. Afterwards about 10 kg of sliced potatoes were used, half of which was uniformly dipped in a mixture of 150 mL of peanut seed oil added with 0.5% (v/v) rosemary essential oil (REO), while the remaining half was dipped into peanut oil and used as control. About 200 g of potatoes, corresponding to an average of 6-8 slices, were placed in sous vide cooking bags, 20×30 cm, by ORVED S.p.A. (Musile di Piave, VE, Italy). The final 50 bags (25 dipped in peanut seed oil + REO, and 25 as control) were vacuumsealed employing a vacuum packaging machine (DELTA 30, FIMA srl, Ariano Irpino, AV, Italy). Sous vide bags sold by ORVED S.p.A. were composed using a bi-layer film made of: bi-oriented polyamide (OPA, 15 μm thick, 17.2 g m-2) for the side not in contact with the product; twocomponent polyurethane (3 g m-2) as adhesive; cast polypropylene (CPP, 60 μm thick, 54 g m-2) for the side in contact with the product, designed for vacuum storage and sous vide cooking up to 121 °C for 30 minutes. All samples were stored under refrigerated conditions at +4 ± 2 °C until cooking; a small portion of each sample was cooked, inside own sous vide bag, by boiling for 15 min at 105 ± 5°C. Finally, cooked samples were kept at -80 ± 5 °C until analysis.
All chemical analyzes were performed in triplicate. All the reagents and solvents for the chemical determinations were purchased from Sigma-Aldrich (Milano, Italy) and were of HPLC grade. Bidistilled water was used throughout this analytical trial.
2.2. Ascorbic Acid content Ascorbic acid content (AsAc) was evaluated considering the ability of AsAc to reduce the dye 2,6dichloroindophenol following the spectrophotometric method used by Burgos et al. (2009) with slightly modifications. Briefly, 15 g of each defrosted sample was extracted with an oxalic acid and acetone solution (0.4 and 20%, respectively) by homogenizing at 4000 rpm for 15 min, filtered through filter paper Whatman n.4 and brought to 100 mL with the same extracting solution. 0.5 milliliter of the extract was reacted with 2 mL of 2,6-dichloroindophenol (prepared according to AOAC official method (2005) and diluted 1:5) during 1 min and read at 520 nm on a spectrophotometer (UV-2401 Shimadzu Co., Japan). Results were expressed as mg on 100 g of fresh weight (FW). Dehydroascorbic acid (DHAA) is present in very low amount in potatoes (Burgos et
al., 2009) so we do not evaluate its concentration. The AsAc concentration was made through comparison with a standard curve of L-Ascorbic acid pure commercial standard (Carlo Erba Reagenti, Milan, Italy).
2.3. Total polyphenol content For the extraction of total polyphenols (TP), we followed the procedure as reported by Lombardo et al., (2013). 2.5 g of defrosted material were treated with 50 mL of ethanol 80% (v/ v), blended for 2 min, stirred at room temperature for 1 h and then centrifuged at 4000 rpm during 15 min. The filtrate (through Whatman No. 4 filter paper) was stored at -80 ± 5 °C until analysis was performed. The Folin-Ciocalteu assay (Singleton and Rossi, 1965) was used to quantify the TP content (TPC). The absorbance was measured at 760 nm using a spectrophotometer (UV-2401 Shimadzu Co., Japan). The TPC was determined on the basis of a standard calibration curve generated with known
amounts of gallic acid (Sigma, Milan, Italy), and results expressed as mg on 100 g of fresh weight (FW).
2.4. Antioxidant activity The antioxidant activity (AA) of the extracts obtained for TPC determination was evaluated as percentage inhibition of DPPH radical (Brand-Williams et al., 1995). An aliquot (0.1 mL) of each extract was added to 3.9 mL of freshly prepared methanolic solution containing 0.24 g L-1 DPPH, and held in the dark for 30 min at room temperature. Then, the absorbance was measured at 515 nm. The percentage inhibition of DPPH was obtained by the following equation: [(AC(0) − AS(t)/AC(0)] × 100, where AC(0) is the absorbance of the blank control at the beginning of the experiment assay, and AS(t) the sample absorbance after 30 min.
2.5. Statistic Bartlett’s test was used to test the homogeneity of variances, following which the data were subjected to a three-way analysis of variance (ANOVA), using CoStat release 6.311 (CoHort Software, Monterey, CA, USA), to determine the effects of “cultivar (6) x treatments (2) x storage time (4)”. Means were compared using least significance difference (LSD) test (P≤0.05).
3. Results and discussion In Table 1 are reported the effect of the different cultivar, storage time, dipping treatment and their interactions on the AsAC, TPC and AA on sous vide cooked potato slices. Results were expressed in mg/100 g of fresh weight (FW) and considering the dry matter content of the individual cultivars, determined on the raw material (Lombardo et al., 2017), concentrations were also expressed in mg/100 g of dry matter (DM). The different cultivars analyzed showed the highest significance for TPC and AA (P<0.001) while it was of P<0.01 for AsAc. As well as the six cultivars, also the storage time was significant in our testing, differently with nutritional components studied after
sous vide cooking. After the analysis of the main effects, as not surprising consequence, only the interaction “cultivar x storage” was significant (P<0.001) for all nutritional traits, while the interaction “cultivar (C) x treatment (T)” was significant only for the value of AA. The sous vide cooking applied for our experiments is near to the boiling applied by Burgos et al., (2009) because bags were placed in a stainless steel pot and cooked over uniform high temperature almost 100 °C but with the difference that the time was shorter, around 13–15 min, so in the middle between time reported for boiling and microwave cooking in the same cited paper (Burgos et al., 2009). Vegetables are a rich source of vitamins and minerals which are lost when they are boiled, steamed, or microwaved while sous vide cooked vegetables, in comparison, retain nearly all their nutritive value because sous vide vegetables leave the cell walls mostly intact (Baldwin, 2012). Considering the dipping treatment (Table 1), the presence of REO had no significant effect on the nutritional characteristic considered in cooked samples, in the same way also interactions between other factors with treatment have no significant differences with the only exception, as said, for the interaction “C x T” for AA. Moreover, from a previous experience where the synergistic use of REO and vacuum packaging, combined with refrigerated storage, had positive effects on the quality preservation of minimally processed potatoes (Rizzo et al., 2018), REO treatment effectiveness was probably much linked to dipping solution, explicating its effect before cooking processing. As reported in literature, generally EO’s have demonstrated antibacterial activity against food borne pathogens, and on the phenolic components, which are most active and appear to be active principally as membrane permeabilisers (Burt, 2004). The AsAc content was slightly low in all samples, ranging from 4.9 to 3.2 mg/100g FW: taking into account that this compound is commonly considered heating sensitive, Elodie cultivar kept the highest AsAc content while Erika kept the lowest (Table 1). The influence of storage was significant different among the cultivars but is explained in a small range of values and the reduction after cooking was confirmed also by Burgos et al. (2009), however it is well known that AsAc is sensitive to air, heat and water, and can easily be destroyed by prolonged storage (Zee et al,
1991). Previously reported values of the AsAc of raw tubers of the same cultivars, on a DM basis ranged from 21.7 to 28.5 mg/100g (Rizzo et al., 2018), while AsAc concentration of sous vide cooked slices were slightly higher than those reported by Burgos et al. (2009) in three cooking methods studied (boiling, baking and microwaving). In particular, considering how the retention values of boiled tubers ranged from 54 to 97%, we can affirm that sous vide cooking probably thanks to the additional treatment with REO, better preserve the AsAc keeping values nearest to the raw tubers with moderate loss to a maximum of 20% in Erika. The AsAc content seems increasing during storage from 2.7 to 4.3 mg/100 g FW after 11 days with a maximum of 5 mg/100 g FW in the sampling carried out after 4 days of storage, probably this path could be explained considering the high variability of the AsAc content available in tested cultivars as reported by Lombardo et al. (2017). TPC is well preserved after cooking, of course the varieties with the highest content are able to save a high amount of the compound studied; Elodie showed the highest TPC followed by Ranomi while the lowest was observed in Arinda cultivar. TPC on raw tubers measured from 2.68 to 4.23 g kg-1 DM (Rizzo et al., 2018), and the concentration after sous vide cooking was from 337 to 257 mg/100 g DM; the results were in line with those reported by Tierno et al. (2015) whom evaluated the effect of boiling on total phenolic values ranged from 142 to 359 mg GAE 100 g-1 DW in raw tubers and confirmed a decreasing for all cultivars studied when the potatoes were boiled from 78.0 to 221 mg GAE 100 g-1 DW. After boiling processing, from 45 to 74% of the TPC was retained for all cultivars, with the exception of the pale yellow-fleshed in which the retention was very much higher (93.5%) as well as in our samples (all yellow-fleshed cultivars) were the retention was from 75 to 96%. TPC values in sous vide cooked samples were consistent with data from raw tuber (Lombardo et al., 2017; Rizzo et al., 2018) underlining the variability inside the same cultivar, but also the protection probably extended by REO. Sure enough the highest values of AsAc and TPC reported during storage, respect to the initial content detected, should be linked to such protections from REO on the phenolic components. From literature there is a clear evidence that the total amount of
phenolics in potato varies significantly among different varieties (Brandl and Herrmann, 1984), as it was also observed for our varieties in the past paper (Rizzo et al., 2018; Lombardo et al., 2017), while this consideration is probably weaker for the same cultivars after sous vide cooking. Significant difference among varieties may be attributed to genotypes and harvest location which influence the accumulation of phenolic compounds, but those aspects are perhaps misplaced with cooking processing. Also, the AA was reduced in sous vide cooked potato slices, with a loss mean value of 48% among cultivars, Fontane showed the highest AA value and Erika the lowest whereas considering the reduction from initial AA on the raw material Elodie kept the highest AA content. In samples cooked after different storage time, was noticed an increasing in AA, as previously reported by Tudela et al. (2002); total flavonoids were induced by the fresh cut process in potatoes and their loss was pronounced during cooking differently among the various cooking practices. Some authors did not find any correlation between the TPC and AA on many plant extracts, but for others, AA in fruit and vegetables was mainly attributed to phenol content, and in some case together with AsAc Cabezas-Serrano et al. (2009). Probably in the present study, as well as reported by Cabezas-Serrano et al. (2009), AA was correlated more with AsAc than with TP. This can be explained by the fact that antioxidant capacity is mainly provided by ascorbic acid, while phenolic contribution to oxidative reaction is more decisive than its antioxidant role. Results of this work confirmed the extreme differences existing among potato varieties in terms of post-cutting performances, and the need to extend the screening to other varieties, in order to have more raw material available for processing according to the season availability. In addition, when the same performances are obtained, the choice may be directed to those varieties with higher nutritional value.
4. Conclusion Looking at the positive results obtained in a past experience, with the synergistic use of REO and vacuum packaging, combined with refrigerated storage on the quality preservation of minimally processed potatoes we hoped to detect such positive effect also after cooking in sous vide on nutritional compounds. Ascorbic Acid, total phenols and antioxidant activity were slightly reduced so well preserved after sous vide cooking. A good result was observed on AsAc, commonly considered heating sensitive, after sous vide cooking it was higher than concentrations reported in literature after different cooking methods, suggesting a good effect of cooking in vacuumized plastic pouches at precisely controlled temperatures. TPC was well preserved after cooking especially in our yellow-fleshed cultivars, and the AA showed a loss mean value of 48% among cultivars. Although the most suitable cultivars identified to be processed in fresh cut potato slices with the addition of REO to be store and then cooked in sous vide bags were Fontane and Marabel (Rizzo et al., 2018), we can assess that the cultivar with the highest nutritive values among cultivars studied is Elodie, with positive results also from the two cultivars previously cited. Nutritional characteristics pointed out in this experiment, on potato slices treated with REO and cooked in sous vide pouches, were kept by the samples, suggesting as more study are require before EO’s and sous vide cooking bags can be reliably used in commercial applications, as well as major investigations should be done on interaction with AsAc in food matrix, the use of EOs in consumer goods is expected to increase in the future due to the rise of ‘green consumerism’ improving nutritive quality for final consumers.
Acknowledgements The authors thank Prof. Giovanni Mauromicale (Catania University) for having provided the tuber material and Dr. Ph D. Stefania Toscano (Catania University) for advice on statistical analyses.
Funding: This work was financially supported by Project “Utilizzo integrato di approcci tecnologici innovativi per migliorare la shelf-life e preservare le proprietà nutrizionali di prodotti agroalimentari (shelf-life)” (PON 02_00451-3361909). Interests statement Conflicts of Interest: The authors declare no conflict of interest.
References Albishi, T., John, J.A., Al-Khalifa, A.S., Shahidi, F., 2013. Phenolic content and antioxidant activities of selected potato varieties and their processing by-products. J. Functional Foods, 5, 590-600. https://doi.org/10.1016/j.jff.2012.11.019. AOAC Official Method 967.21. (2005). Ascorbic acid in vitamin preparations and juices. 2,6dichloroindophenol titrimetric method, 45.1.14. , J. AOAC Int., 45, 22-23 Augustin, J., Johnson, S.R., Teitzel, C., True, R.H., Hogan, J.M., Toma, R.B., Shaw, R.L., Deutsch, R.M., 1978. Changes in the nutrient composition of potatoes during home preparation. II. Vitamins. Am. Potato J. 55, 653–662. https://doi.org/10.1007/BF02852138. Baldwin, D.E., 2012. Sous vide cooking: A review. Int. J. Gastronomy and Food Science, 1, 15-30. https://doi.org/10.1016/j.ijgfs.2011.11.002 Brandl, W., Herrmann, K., 1984. Occurrence of chlorogenic acid in potatoes. Zeitschriftfur Lebensmittel-Untersuchung
und
-
Forschung,
178,
192–194.
https://doi.org/10.1007/BF01043358. Brand-Williams, W., Cuvelier, M. E., Berset, C., 1995. Use of a free radical method to evaluate antioxidant
activity.
Lebensmittel-Wissenschaft
https://doi.org/10.1016/S0023-6438(95)80008-5.
und
-Technologie,
28,
25–30.
Burgos, G., Auqui, S., Amoros, W., Salas, E., Bonierbale, M., 2009. Ascorbic acid concentration of native Andean potato varieties as affected by environment, cooking and storage. J. Food Comp. Anal. 22, 533–538. https://doi.org/10.1016/j.jfca.2008.05.013. Burt S. (2004). Essential oils: their antibacterial properties and potential applications in foods – a review. Int. J. Food Microb. 94, 223–253. Cabezas-Serrano, A. B., Amodio, M. L., Cornacchia, R., Rinaldi, R., & Colelli, G. (2009). Suitability of five different potato cultivars (Solanum tuberosum L.) to be processed as fresh-cut products. Post. Harvest Biol and Technology, 53, 138–144. Fabbri, A.D.T., Crosby G.A., 2016. A review of the impact of preparation and cooking on the nutritional quality of vegetables and legumes. Int. J. Gastronomy and Food Science, 3, 2-11. https://doi.org/10.1016/j.ijgfs.2015.11.001. Hesam, F., Balali, G.R., Tehrani, R.T., 2012. Evaluation of antioxidant activity of three common potato (Solanum tuberosum) cultivars in Iran. Avicenna J Phytomed., 2(2), 79–85. https://doi.org/10.22038/ajp.2012.36. Lešková, E., Kubíková, J., Kováčiková, E., Košická, M., Porubská, J., Holčíková, K., 2006. Vitamin losses: Retention during heat treatment and continual changes expressed by mathematical
models.
J.
Food
Comp.
Anal.
19
(4),
252–276.
https://doi.org/10.1016/j.jfca.2005.04.014. Lombardo, S., Pandino, G., Mauromicale, G., 2013. The influence of growing environment on the antioxidant and mineral content of “early” crop potato. J. Food Comp. Anal., 32 (1), 28-35. https://doi.org/10.1016/j.jfca.2013.08.003. Lombardo, S., Pandino, G., Mauromicale, G., 2017. The effect on tuber quality of an organic versus a conventional cultivation system in the early crop potato. J. Food Comp. Anal., 62, 189-196. http://doi.org/10.1016/j.jfca.2017.05.014.
Manach, C., Scalbert, A., Morand, C., Rémésy C., Jiménez L., 2004. Polyphenols: Food sources and
bioavailability.
Am.
J.
Clinical
Nutrition,
79
(5),
727–747.
https://doi.org/10.1093/ajcn/79.5.727. Mishra, J.B., 1985. Effect of conditions of storage on ascorbic acid content and sprouting of tubers of some Indian potato varieties. J. Indian Potato Assoc. 12 (3&4), 158–164. Rivero, R.C., Rodríguez, E.R., Romero, C.D., 2003. Effects of current storage conditions on nutrient retention in several varieties of potatoes from Tenerife. J. Food Chem. 80, 445–450. https://doi.org/10.1016/S0308-8146(02)00281-9. Rizzo, V., Amoroso, L., Licciardello, F., Mazzaglia, A., Muratore, G., Restuccia, C., Lombardo, S., Pandino, G., Strano, M. G., Mauromicale, G., 2018. The effect of sous vide packaging with rosemary essential oil on storage quality of fresh-cut potato. LWT - Food Science and Technology, 94, 111–118. https://doi.org/10.1016/j.lwt.2018.04.033. Schellekens, M., 1996. New research issues in sous-vide cooking. Trends in Food Science and Technology 7 (8), 256–262. https://doi.org/10.1016/0924-2244(96)10027-3. Shahidi, F.(2000). Antioxidants in food and food antioxidants. Nahrung – Food,44, 158–163. Singh, P.P., Saldaña, M.D.A., 2011. Subcritical water extraction of phenolic compounds from potato peel. Food Res. Int., 44 (8), 2452-2458. https://doi.org/10.1016/j.foodres.2011.02.006. Singleton, V.L., Rossi, J.A., 1965. Colorimetry of total phenolics with phosphomolybdic phosphotungstic acid reagents. Am J Enol Vitic. 16, 144–158. Suárez, H.P., Rodríguez, R.E.M., Díaz, R.C., 2004. Cambios en el valor nutritivo de patatas durante distintos
tratamientos
culinarios.
Cienc.
Tecnol.
Aliment.
4
(4),
257–261.
https://doi.org/10.1080/11358120409487768. Tierno, R., Hornero-Méndez, D., Gallardo-Guerrero, L., López-Pardo, R., Ruiz de Galarreta, J.I,. 2015. Effect of boiling on the total phenolic, anthocyanin and carotenoid concentrations of potato tubers from selected cultivars and introgressed breeding lines from native potato species. J. Food Comp. Anal. https://doi.org/10.1016/j.jfca.2015.01.013
Tudela, J.A., Cantos, E., Espín, J.C., Tomás-Barberán, F.A., Gil, M.I., 2002. Induction of antioxidant flavonol biosynthesis in fresh-cut potatoes. Effect of domestic cooking. J. Agric. Food Chem., 50 (21), 5925-5931. https://doi.org/10.1021/jf020330y. Zee, J.A., Carmichael, L., Codère, D., Poirier, D., Fournier, M., 1991. Effect of storage conditions on the stability of vitamin C in various fruits and vegetables produced and consumed in Quebec. J. Food Comp. Anal. 4 (1), 77–86. https://doi.org/10.1016/0889-1575(91)90050-G.
Table 1. Mean effects of six cultivar (C) and two dipping treatments (T) during storage time (S) on ascorbic acid, total polyphenol content and antioxidant activity on sous vide cooked potato slices. Dipping treatmenta Cultivar (C) Arinda Elodie Erika Fontane Marabel Ranomi A B Storage (d) 0 4 7 11
AsAc (mg/100 g FW)
AsAc (mg/100 g DM)
TPC (mg/100 g FW)
TPC (mg/100 g DM)
AA (% DPPH inhibition)
4.2±0.27ab 4.9±0.20a 3.2±0.28c 4.1±0.19b 4.0±0.20bc 3.8±0.25bc
25.32±15.40b 30.42±12.51a 18.00±15.41c 23.21±10.47b 26.31±12.97b 24.83±16.02b
45.3±0.80d 53.3±0.81a 50.3±0.58ab 46.5±0.58cd 49.3±0.78bc 51.9±0.79ab
257.4±154.38b 332.9±106.77a 276.5±116.51a 259.6±125.02b 320.4±108,66a 336.8±113,57a
17.89±4.46bc 17.72±5.83bc 16.50±7.02c 21.54±4.06a 17.94±2.75bc 18.76±4.11b
4.1±0.23 4.0±0.24
25.12±14.24 24.22±14.02
49.3±0.68 49.6±0.86
296.2±155.02 298.3±154.78
18.23±5.59 18.55±4.47
2.7±0.23c 5.0±0.13a 4.1±0.29b 4.3±0.20ab
18.25±14.05c 29.67±13.79a 24.57±14.42b 26.23±13.74b
52.9±0.95a 48.8±0.83b 49.2±0.60b 46.8±0.51b
318.7±157.39a 293.8±172.76b 294.8±126.56b 281.8±127.89b
14.58±6.67c 21.39±4.37a 19.42±2.89b 18.19±2.51b
time
Main effect Cultivar (C) Dipping treatmenta (T) Storage time (S) Interaction CxT CxS TxS
**
***
***
NS
NS
NS
***
**
***
NS *** NS
NS *** NS
*** *** NS
Note: AsAC: ascorbic acid content; TPC: total polyphenol content; AA: antioxidant activity; ***, ** and *
indicate significant at P <0.001, P<0.01 and P<0.05, and NS, not significant. Different letters
indicate statistical differences for P ≤ 0.05. a
A: dipping in peanut oil; B: dipping in peanut oil and rosemary essential oil.