Changes in lycopene content and quality of tomato juice during thermal processing by a nanofluid heating medium

Accepted Manuscript Changes in lycopene content and quality of tomato juice during thermal processing by a nanofluid heating medium

Seyyed Sajjad Jabari, Seid Mahdi Jafari, Danial Dehnad, Seyyed Ahmad Shahidi PII:

S0260-8774(18)30075-X

DOI:

10.1016/j.jfoodeng.2018.02.020

Reference:

JFOE 9175

To appear in:

Journal of Food Engineering

Received Date:

11 October 2017

Revised Date:

19 February 2018

Accepted Date:

21 February 2018

Please cite this article as: Seyyed Sajjad Jabari, Seid Mahdi Jafari, Danial Dehnad, Seyyed Ahmad Shahidi, Changes in lycopene content and quality of tomato juice during thermal processing by a nanofluid heating medium, Journal of Food Engineering (2018), doi: 10.1016/j.jfoodeng. 2018.02.020

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ACCEPTED MANUSCRIPT Changes in lycopene content and quality of tomato juice during thermal processing by a nanofluid heating medium

Running title: Nano-fluid thermal processing of tomato juice Seyyed Sajjad Jabari, Seid Mahdi Jafari, Danial Dehnad, Seyyed Ahmad Shahidi

Graphical Abstract:

Intelligent thermal/heating system for nanofluids (1) Insulated stainless steel shell and tube heat exchanger, (2) PT100 Sensors, (3) Nanofluid reservoir, (4) Food liquid reservoir, (5) Stainless steel centrifugal pump, (6) N700E vector inverter, (7) Digital contour, (8) PLC section

ACCEPTED MANUSCRIPT

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Changes in lycopene content and quality of tomato juice during thermal processing by a

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nanofluid heating medium

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Running title: Nano-fluid thermal processing of tomato juice Seyyed Sajjad Jabaria, Seid Mahdi Jafari*b, Danial Dehnadb, Seyyed Ahmad Shahidic

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a Young

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bDepartment

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Sciences and Natural Resources, Gorgan, Iran; Tel./fax: +98 17 324 26 432.

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cDepartment

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Researchers and Elite Club, Ayatollah Amoli Branch, Islamic Azad University, Amol, Iran of Food Materials and Process Design Engineering, Gorgan University of Agricultural of Food Science and Technology, Ayatollah Amoli Branch, Islamic Azad University,

Amol, Iran *Corresponding author: [email protected]

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Abstract

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The main aim of this study was to evaluate the effects of shortening common thermal processing

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through nanofluids on quality of tomato juice for the first time. For this purpose, three different

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temperatures (between 70 and 90°C), nanoparticle concentrations (between 0 and 4%) and time

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(between 30 and 90 s) were selected for thermal processing of tomato juice in a shell and tube heat

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exchanger through central composite design. The findings indicated that while 4% nanoflluid at 30 °C

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for 30 s led to the best lycopene retention (96%) of tomato juice, hot water treatment (0% nanoparticle

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concentration) at 90 °C for 90 s resulted in the lowest lycopene retention (67%). The durations required

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for product to reach a certain temperature were dwindled and treated samples experienced lower color

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drops when higher nanoparticle concentrations were applied; a*/b* indices at 80°C were 1.7, 1.8 and

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1.9 for 0, 2 and 4% nanoparticles, respectively; indeed, higher nanoparticle concentration, and lower

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temperature and time led to higher lycopene retention and, as a consequence, higher a*/b* values. The

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effect of time on pH and acidity indices was not significant while temperature influenced those

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parameters significantly. Based on the indices considered, if temperature, concentration and time are

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set at 70°C, 4% and 30 s, the best responses will be obtained.

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Keywords: Nanofluids; Tomato juice; Heat exchanger; Nutritional properties. 1

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1. Introduction

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Tomato is the second most important produce around the world economically and planted in nearly all

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countries. Lycopene has the greatest contribution (around 83%) to the total pigments present in the

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tomatoes and is regarded as the most abundant carotenoid in this fruit (Shi et al., 1999). Besides, this

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pigment is the most important chemical compound in tomatoes, capable of neutralizing free radicals in

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human body with its antioxidant characteristics and preventing human being to be affected by cancer,

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accelerated aging, cardiovascular diseases, osteoporosis, diabetes, and lots of other diseases (Basiri,

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2008). Considering above-mentioned points and high nutritional value of tomato, developing a

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technology capable of producing high quality product and accessible throughout the year in every

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condition is really beneficial (Jafari et al., 2017a). One of these suggested methods is thermal

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pasteurization used for long-term storage of fruit juices, especially tomato juice.

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Thermal processing of food products, in particular pasteurization of milk products, fruit juices,

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concentrates, and formulations, is one of operational units in the food industry, applied for

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improvement of their qualitative properties and extending their storage time. This process may be

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deployed for rapid heating of food products to at least 78°C. Although this processing is effective in

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inactivation of microorganisms and enzymes, it could be detrimental to the quality of fruit juices.

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During thermal processing, structural, and, in consequence, physical, chemical and biochemical

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changes in matrices of food products occur. If thermal processing is not applied rapidly or at

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reasonably minimal temperatures, fruit juices start to scatter in two phases due to pectin destruction

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(Goodman et al., 2002). So, today, one of the issues discussed in heat processing is the necessity of

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considerable increase in heat flux while minimizing heat transfer equipment required in the food

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industry.

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Because of issues above-mentioned, diverse methods have been applied for escalating heat transfer

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efficiency; however, all these methods were restricted on account of weak characteristics of

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conventional heat transfer fluids, e.g. water. In comparison with other fluids at larger dimensions than

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nano-scale, in particular micro scale, a remarkable raise in thermal conductivity is the most important

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effect observed for nano-scale fluids so that even at low concentrations of nanoparticles (1-5%v/v),

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thermal conductivity could be increased by more than 20% (Xuan and Li, 2003). Besides, nanofluids

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show high stability. Accordingly, nanofluids have attracted high attentions recently and a lot of

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researches have been carried out on this subject by now. Wen and Ding (2004) investigated the

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convective heat transfer of nanofluids (Al2O3 nanoparticles and de-ionized water) in the laminar flow

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regime. Their results showed a significant raise in convective heat transfer using the nanofluids, due to

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more thermal conduction, nanoparticles migration, and the consequent disturbance of the boundary

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layer. Nasiri et al. (2011) investigated heat transfer capacity of Al2O3/H2O and TiO2/H2O nanofluids

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through a circular channel for a turbulent flow mode. Based on their results, for any specific Peclet

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number, Nusselt number of nanofluids was higher than that of the base fluid and there was a direct

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relationship between the nanoparticle concentration and performance improvement for both nanofluids.

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However, heat transfer improvements for those nanofluids were similar. Our previous works on

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nanofluids thermal processing of fruit juices had been implemented for the first time in food products

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and it was shown that alumina could be a very good nanoparticle to be deployed for heat transfer

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purposes in other industries than common ones, including the food industry (Jafari et al., 2017b-e).

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In conclusion, the aim of this research was to intensify heat transfer efficiency in shell and tube heat

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exchangers, thereby retaining quality and nutritional properties, particularly lycopene content, of

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tomato juices during thermal processing more efficiently.

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2. Materials and methods

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2.1. Preparing the product

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Fresh tomatoes were purchased from a local fruit market (Gorgan, Iran) and stored at 3±1°C. At the

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appropriate time, they were crushed using a domestic juice extractor (MJ-W176P, Panasonic, Japan).

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The juice was filtered on a sterile double layer cheese cloth to remove seeds from the juice, and

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processed subsequently (Adekunte et al., 2010).

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2.2. Nano-fluid preparation

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Alumina nano-particles with 99% purity (US research nano-materials, Inc.) were purchased and

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dispersed with different volume concentrations of 0, 2 and 4% w/v in deionized distilled water. Then, it

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was stirred completely for an hour with a heater-stirrer at 1500 rpm in order to ensure nano-fluid

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stability (Jafari, et al., 2017b). No sedimentation was observed in the prepared nanofluid after 24 h. The

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details of nanoparticle properties are represented in Table 1. These alumina nano-particles were used in

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the heat exchanger as a part of the heating medium, but there was no direct contact between nanofluids

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and the product.

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Table 1

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2.3. Intelligent thermal processing system

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This system contains a shell and tube heat exchanger, two separate reservoirs, one for liquid food, and

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the other one equipped with a 1kw heater for heating the fluid (water or nano-fluid) and flow loop tubes

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for transferring the fluids from the reservoir to the heat exchanger, which means there is no contact

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between food and fluid throughout the system. Different parts of the intelligent thermal systems were

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shown in Fig. 1; complete descriptions of the equipment were represented by Jafari et al. (2017c) and

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Jafari et al. (2018a).

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Fig. 1. 4

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2.4. Lycopene determination

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5 mL of 95% ethanol, 5 mL 0.05% (w/v) of butylated hydroxytoluene in acetone, 10 mL of hexane and

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approximately 0.6 g of tomato juice were added to dark bottles. After 15 min stirring of the content

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with a magnetic stirrer (60F, FALC, Italy), 3 mL of deionized water was added to each bottle, and the

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bottles were shaken again for 5 min. A spectrophotometer (UV/VIS80, PG, UK) was used to analyze the

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upper hexane layer of each sample at 503 nm wavelength. Hexane was our blank sample. Finally,

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following equation was used to calculate lycopene content (Fish et al., 2002):

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Lycopene (mg/kg juice) =

A503 × 31.2

(1)

g juice

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Where 31.2 refers to the molar extinction coefficient, lycopene retention was calculated using equation

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(2):

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Retention (%) = mg lycopene/kg juice before treatment × 100

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2.5. Color analysis

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The samples were analyzed for a*/b* (red–green/ yellow–blue) color parameter using a chromameter

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(loviband CAM-System 500, Switzerland). This color index has been used in expressing color changes

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in commercial tomato products. The samples were placed on transparent plates and a few points were

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selected at random; the means were reported (Ganje et al., 2016).

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2.6. pH

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pH measurements were carried out using a digital pH meter (W3B, BEL, Italy) at room temperature.

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pH meter was calibrated using pH=7 and pH=4 buffers in advance. Three different points of each

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sample were selected and the mean values were reported (Jafari et al., 2018b).

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2.7. Acidity

mg lycopene/kg juice after treatment

5

(2)

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Acidity rate of tomato juices was measured by the potentiometric method (ISIRI, 2012). First, pH

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meter was calibrated with pH=7 and pH=4 buffers. Then, 50 mL of distilled water was boiled, cooled

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and displaced to a beaker. After that, 20 g of tomato juice was added and it was located on a heater

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stirrer. The probe of pH-meter was placed into the beaker. Both heater stirrer and pH meter were turned

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on. 0.1 N NaoH was added until pH of the tomato juice reached 8.1. Then, the volume of NaOH

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consumed was read and acidity was calculated by the following equation:

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𝐀=

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where, V, M and A are volume of consumed 0.1 N NaOH (mL), weight of the sample (g), and total

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acidity in terms of citric acid (g/100g), respectively. 1 mL of 0.1 M NaOH is equivalent to 0.0064 g of

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citric acid.

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2.8. Statistical analysis

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Three different temperatures, nanoparticle concentrations and durations were selected to treat tomato

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juices (Table 2). To opt the best fitting models and for regression analysis, Design-Expert® 6.0.2

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software was applied. Selected methodology and design were Response Surface and Central

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Composite, respectively, which were used to survey the effects of variables on responses (p<0.05).

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Table 2

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3. Results and discussion

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3.1. Influence of nanofluids thermal processing on the lycopene content

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According to Table 3, all three factors had significant effects on lycopene content of tomato juices (p

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< 0.05). Untreated tomato juice had 46.7 mg/kg lycopene content; so, treatments No. 4 and 5, having

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the highest (45.0 mg/kg) and lowest (31.2 mg/kg) lycopene contents among all treated samples, led to

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lycopene retention percentages of 96.2 and 66.8%, respectively. Considering F values, temperature had

𝐕 × .𝟎𝟎𝟔𝟒 × 𝟏𝟎𝟎 𝐦

(3)

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the highest effect on this parameter (258.2); similarly, concentration had more considerable influence

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on lycopene content than time, and higher lycopene content was maintained at higher nanoparticle

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concentrations, due to more rapid heat transfer and lower processing time at this state. As a rule, higher

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lycopene contents were caused by higher nanoparticle concentrations and lower temperature or time. In

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Fig. 2a, steeper slope of the graph on temperature side compared with time side hints deeper effect of

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temperature than time on this index, confirming the results of F value; lycopene content descended

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when temperature and time declined. As the Fig. 2a depicts, the highest lycopene content (42 mg/kg)

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was obtained at the lowest temperature and time; in contrast, the highest temperature and time led to

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the lowest lycopene content (32 mg/kg).

147

Table 3

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Fig. 2

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The main reasons of lycopene destruction at higher temperatures are isomerization and oxidation

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(Giovanelli and Paradiso, 2002). Besides, environmental factors including air, light and temperature

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might change the influencing rates of these two processes on lycopene content of tomato products

152

(Anguelova and Warthesen, 2000). Goula and Adamopoulos (2006) reported that destruction of

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lycopene during thermal treatment of tomato products is affected by oxygen, light, humidity and

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temperature; all of which are dependent on the temperature of the product.

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However, light thermal treatment can retain lycopene content and improve its bioavailability due to

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the release of chemical substances of plants from their matrices, facilitating lycopene extraction

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(Gartner et al., 1997). Cis-isomers of lycopene intensify by increasing thermal time, the antioxidant

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activity potentials of which are nearly twice those of β-carotene trans-isomers (Bohm et al., 2002).

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D’Evoli et al. (2013) suggested that thermal processing and homogenization damage cellular

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membrane and protein-carotenoid complexes, and make these carotenoids more available. 7

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3.2. Influence of nanofluids thermal processing on the color changes

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According to the Table 3, all the factors had significant effects on this response. As far as the F value is

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concerned, temperature had the most considerable influence, with nanoparticle concentration and time

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coming next, respectively. The a*/b* index for unprocessed tomato juices was 2.2; the highest and

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lowest rates of this index were 2.2 and 1.5 for treatment numbers 4 and 5, respectively. Table 4

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represents coefficients of the final model and different variables for that model; linear model was the

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most appropriate factor for this index. Generally, lower temperatures and time, and higher nanoparticle

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concentrations could improve a*/b* index. Figure 2b shows simultaneous effect of temperature and

169

concentration on the color. The highest color retention was relevant to the treatments with the highest

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nanoparticle concentrations and lowest temperatures. In fact, higher concentrations caused the duration

171

needed to reach a given temperature to dwindle and those samples experienced lower color drops. For

172

example, a*/b* indices at 80°C were 1.7, 1.8 and 1.9 for 0, 2 and 4% nanoparticles, respectively;

173

indeed, the effect of concentration was really minimal in comparison with temperature. Color changes

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in the graph during the temperature increase and color stability despite the concentration increase

175

illustrate their affecting types.

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Table 4

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The effect of each treatment on color changes could be attributed to its impact on lycopene content.

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Indeed, those treatments which resulted in higher lycopene content, discussed in the previous section,

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led to higher a*/b* values.

180

Our results suggested that higher temperatures decreased L* and a* values while increasing b*

181

value. Cortes et al. (2008) reported that thermal treatment at 90°C for 20 s intensified b* values of

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processed orange juices, compared with raw orange juices, considerably. According to Lee and Coates

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(2003), thermal treatment (90°C for 30 s) increased and decreased a* and b* values, respectively. 8

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Generally, color changes in food products during thermal processing are due to internal reactions

185

such as colorants destruction (especially carotenoids and chlorophylls), browning reactions, e.g.

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Millard reactions with hexoses and amino acids, and ascorbic acid oxidation (Barreiro et al., 2000; Lee

187

and Coates, 1999; Lozano and Ibarz, 1997). So, final color parameters of the products could be used as

188

an index to evaluate quality loss due to thermal processing (Shin and Bhownik, 1995).

189

De Souza et al. (1999) reported L* and a* values are linked to lycopene content whereas b* values

190

have slight correlations with this index. Klim and Nagy (1988) reported that the reason of a decrease in

191

L* value during thermal treatment is formation of dark compounds by non-enzymatic browning,

192

resulting in a drop in desirability of fruit juices. In thermo-processed tomato juices, the probability of

193

enzymatic browning by enzyme activity of polyphenolase in oxygen presence is negligible in viewing

194

of application of heating throughout processing, inactivity of polyphenol oxidase enzyme and

195

deaeration, and ascorbic acid destruction most leads to the production of brown pigments through

196

anaerobic pathways (Porretta, 1991). Krebbers et al. (2003) and Shi and Le Maguer (2000) expressed

197

that low ratio of a*/b* represents orange to brown colors, the reasons of which are lycopene destruction

198

and Millard reaction through intense thermal operations. In fact, lycopene destruction is associated with

199

a decrease in L* and a* values of tomato juices.

200

3.3. Influence of nanofluids thermal processing on the acidity changes

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As shown in Table 5, the effect of time on this index was not significant while temperature and

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nanoparticle concentrations influenced it significantly. Acidity of unprocessed tomato juices was 0.421

203

mg/100g in terms of citric acid. Treatments No. 16 and 5 had the highest and lowest acidity rates with

204

0.42 and 0.35 mg/100g, respectively. The F values reveal that the effect of temperature was much

205

deeper than time and concentration on this index. For predicting the acidity, linear model was the most

206

appropriate model. Fig. 3a monitors simultaneous effect of temperature and concentration on acidity. 9

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The highest acidity belonged to the base fluid (water) at the lowest temperature, and the lowest acidity

208

to the 4% nanofluid at the highest temperature. As Fig. 3a indicates at low temperatures, a slight

209

reduction in acidity occurred when nanoparticle concentration decreased, attributed to longer time

210

needed at lower concentrations. Also, the slope of the graph clearly reveals the more profound effect of

211

temperature, compared with concentration, on this index.

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Table 5

213

Fig. 3

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Sherkat and Bor (1976) reported that escalating the temperature of hot break process from 64 to

215

104°C caused pH and acidity to raise and drop, respectively, probably due to rapid inactivation of

216

pectin esterase and polygalacturonase which hydrolyze pectic substances into pectic acid and

217

galacturonic acid, resulting in acidity decrease and pH increase. Edalatian et al. (2006) attributed high

218

acidity at low temperatures to production or increase in a series of organic acids during long time of

219

processing or storage; as an example, pyrrolidine carboxylic acid is produced during storage time.

220

Pectin breaking and producing miscellaneous acids were mentioned as other probable reasons.

221

3.4. Influence of nanofluids thermal processing on the pH values

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Table 5 represents ANOVA results for pH changes in the products of different treatments. Only

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significant factors were temperature and temperature-concentration. pH value for unprocessed tomato

224

juices was 4.4; the highest and lowest pH rates were 4.6 and 4.42 for treatments number 5 and 16,

225

respectively. It deserves to point out that the pH range of tomato juice after processing was narrow and

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near to the pH value of unprocessed juice, indicating that natural pH value of tomato juice was

227

maintained through nanofluid thermal processing. Although nanoparticle concentration changes were

228

not effective on pH alterations, its interaction with temperature left significant effects on this index.

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Linear effect of temperature had higher influence on pH rates than temperature-concentration with F

230

value of about 308.7. The latter issue could be recognized in the Fig. 3b in which the slope of graph is 10

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higher on temperature side than another side. The highest pH value was observed at the highest

232

temperature and lowest nanoparticle concentration in heating fluid; on the other hand, the least amount

233

was detected at the minimal concentration and temperature.

234

Our results of pH index were in correlation with acidity results; in other words, high acidities

235

accompanied by low pH values, and vice versa. pH drop at low temperatures could be ascribed to

236

microbial spoilage since microorganisms can ferment organic acids, reduce acidity and cause spoilage

237

in fruit juices simultaneously (Sodeko et al., 1987). Nevertheless, pH values were not impacted by

238

thermal treatments substantially, moving in the range of 4.4-4.6. Similarly, Elez-Martinez et al. (2006)

239

reported that thermal processing (at 90°C for 1 min) had minimal effects on physical properties

240

including pH and total soluble solids of orange juices. In the same way, Yeom et al. (2000) observed

241

that pH and total solids of orange juices were not affected by thermal processing at 94.6°C for 30 s.

242

Similar parallel studies confirmed our results as some indicators of food products, i.e. pH of

243

watermelon juice and TSS of tomato juice, were not impacted by nanofluids thermal processing

244

substantially (Jafari et al., 2017b,d).

245

3.5. Influence of nanofluids thermal processing on the process time

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Both nanofluids and treated tomato juice through them reached the maximal temperature earlier than

247

base fluids and tomato juice treated by them when the pump turned on. A substantial reduction in

248

processing time could be observed from 54 min for hot water processing to 42 and 29% for 2 and 4%

249

nanofluids processing, respectively. Indeed, 22.2 and 46.3% drop in duration of thermal processing

250

were achieved when hot water was replaced with alumina nanofluids. In general, both temperature of

251

pasteurization and duration required for it were shortened by half when nanofluids, compared with

252

water, were applied.

253 254

Inherent properties of nanofluids and their impacts on thermal properties are responsible for reduction of processing times by nanofluids. The improvement in conductive heat transfer coefficient 11

ACCEPTED MANUSCRIPT 255

of nanofluids is due to the growth of their thermal conductivity, turbulence strengthening, Brownian

256

motion of spherical nanoalumina, cessation of boundary layer growth, homogenous dispersion of

257

suspended particles and their disordered shifting (Choudhury et al., 2014; Keblinski et al., 2002).

258

3.6. Modelling and optimization procedure

259

Optimization targets were defined as lycopene to be preserved at its maximum values, color values to

260

remain at higher rates than 1.8, and acidity and pH to be maintained in their conventional ranges.

261

Considering these conditions, provided that temperature, concentration and time are set at 70°C, 4%

262

and 30 s, overall desirability of 95% could be attained.

263

4. Conclusion

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The highest lycopene content (45 mg/kg) in treated tomato juice were achieved when higher

265

nanoparticle levels and lower temperature or time during thermal processing were applied. Based on F

266

values obtained from ANOVA Tables, the impact of independent variables on color parameters (a*/b*

267

value) of tomato juice treated by nanofluids was in this order: temperature, nanoparticle concentration

268

and time. Our results suggested that increasing temperature decreased a* values while increasing b*

269

value. Concentration of nanoparticles did not change the original pH and acidity values of tomato juice

270

significantly, but higher lycopene content of tomato was maintained in treated tomato juice after

271

nanofluid processing compared with common thermal processing (with hot water). Linear models

272

could successfully fit the data related to changes in each response at different levels of independent

273

variables. For the first time, these results propose that quality of tomato juice could be improved if

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nanofluid thermal technology is substituted for traditional thermal processing. Our future works include

275

application of this system for other sensitive food products (especially with microbial hazards e.g. milk

276

products); also, sensory analyses will be carried out to examine recognition of changes by consumers as

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a step toward industrialization of nanofluids.

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Acknowledgment 12

ACCEPTED MANUSCRIPT 279

It is necessary to appreciate Iran National Science Foundation (INSF) for the financial support.

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ACCEPTED MANUSCRIPT Fig. 1. Intelligent thermal/heating system for nanofluids Fig. 2. Simultaneous effect of (a) temperature –time on lycopene changes and (b) temperature – concentration on color changes of treated tomato juices Fig. 3. Simultaneous effect of temperature –concentration on changes in (a) acidity and (b) pH values of treated tomato juice through nanofluids

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Fig. 1 Intelligent thermal/heating system for nanofluids (1) Insulated stainless steel shell and tube heat exchanger, (2) PT100 Sensors, (3) Nanofluid reservoir, (4) Food liquid reservoir, (5) Stainless steel centrifugal pump, (6) N700E vector inverter, (7) Digital contour, (8) PLC section

1

ACCEPTED MANUSCRIPT

(a)

(b) Fig. 2 Simultaneous effect of (a) temperature –time on lycopene changes and (b) temperature – concentration on color changes of treated tomato juices

2

ACCEPTED MANUSCRIPT

(a)

(b) Fig. 3 Simultaneous effect of temperature –concentration on changes in (a) acidity and (b) pH values of treated tomato juice through nanofluids

3

ACCEPTED MANUSCRIPT Highlights:



The main goal was thermal processing of tomato juice by nanofluids.



4% nanoflluid at 30°C for 30 s resulted in 96% lycopene retention.



Higher nanoparticle concentrations reduced the time needed for the process.



Nanofluid processing retained the natural pH, acidity and color of product.

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Table 1 Thermophysical properties of alumina nanoparticles used in this research Properties

Description

Average nanoparticle diameter (nm)

20

Density (kg m-3)

3890

Heat capacity (J kg-1 K-1)

880

Thermal conductivity (W m-1 K-1)

36

Base fluid

Water

Morphology

Nearly spherical

1

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Table 2 Design of experiments by central composite design for tomato juices treated by nanofluids at different concentrations, temperatures and time Number of treatment

Time (sec)

Temperature (°C)

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20

90 90 60 30 90 60 90 90 60 60 60 60 30 30 60 30 60 60 30 60

90 70 80 70 90 80 80 70 80 70 80 80 80 90 80 70 90 80 90 90

2

Nanoparticle concentration (%) 4 0 4 4 0 2 2 4 2 2 2 0 2 0 2 0 2 0 4 2

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Table 3 ANOVA data for changes in lycopene content and color (a*/b*) parameter of tomato juice induced by thermal processing through nanofluids Property of

Source

Sum of Squares

DF

Mean Square

F Value

Prob>F

Model

1.74

3

0.58

99.2

< 0.0001

x1

0.047

1

0.047

8.1

0.0117

x2

1.51

1

1.51

258.18

< 0.0001

x3

0.18

1

0.18

31.33

< 0.0001

Residual

0.093

16

5.83E-03

Lack-of-Fit

0.076

11

6.93E-03

2.03

0.2243

Pure Error

0.017

5

3.41E-03

Model

0.62

3

0.21

160.27

< 0.0001

x1

0.027

1

0.027

20.93

0.0003

x2

0.56

1

0.56

432.8

< 0.0001

x3

0.035

1

0.035

27.1

< 0.0001

Residual

0.021

16

1.29E-03

Lack-of-Fit

0.019

11

1.69E-03

4.05

0.0671

Pure Error

2.08E-03

5

4.16E-04

tomato juice Lycopene

a*/b* Value

3

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Table 4 Model coefficients and statistics indices of content changes induced by thermal processing through nanofluids Variable

Model

R2

Pred R2

SD

Lycopene content (mg/100gr)

9.18-0.002x1-0.038x2+0.067x3

0.94

0.91

0.0760

Color (a*/b*)

3.75-1.73x1-0.023x2+0.029x3

0.96

0.94

0.0360

0.62+0.002x1-0.00029x2-0.00017x3

0.91

0.81

0.0007

7.67x2-8.127 x2x3

0.96

0.85

0.0120

Acidity (mg/100gr) pH

4

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Table 5 ANOVA data for changes in acidity and pH values of tomato juice induced by thermal processing through nanofluids Property of tomato juice Acidity

pH

Source

Sum of Squares

DF

Mean Square

F Value

Prob>F

Model

8.88E-03

3

2.96E-03

54.42

< 0.0001

x1

3.60E-06

1

3.60E-06

0.066

0.8003

x2

8.76E-03

1

8.76E-03

161.06

< 0.0001

x3

1.16E-04

1

1.16E-04

2.13

0.046

Residual

8.70E-04

16

5.44E-05

Lack-of-Fit

7.39E-04

11

6.72E-05

2.56

0.155

Pure Error

1.31E-04

5

2.63E-05

0.049

6

8.12E-03

54.19

< 0.0001

x1

4.00E-05

1

4.00E-05

0.27

0.614

x2

0.046

1

0.046

308.66

< 0.0001

x3

9.00E-05

1

9.00E-05

0.6

0.4522

x1x2

1.13E-04

1

1.13E-04

0.75

0.4019

x1x3

1.13E-04

1

1.13E-04

0.75

0.4019

x2x3

2.11E-03

1

2.11E-03

14.1

0.0024

Residual

1.95E-03

13

1.50E-04

Lack-of-Fit

1.41E-03

8

1.77E-04

1.66

0.2996

Pure Error

5.33E-04

5

1.07E-04

Model

5