The influence of almond flour, inulin and whey protein on the sensory and microbiological quality of goat milk yogurt

Journal Pre-proof The influence of almond flour, inulin and whey protein on the sensory and microbiological quality of goat milk yogurt Agata Mazzaglia, Veronika Legarová, Rossella Giaquinta, Carmela Maria Lanza, Cristina Restuccia PII:

S0023-6438(20)30126-2

DOI:

https://doi.org/10.1016/j.lwt.2020.109138

Reference:

YFSTL 109138

To appear in:

LWT - Food Science and Technology

Received Date: 11 January 2018 Revised Date:

16 January 2020

Accepted Date: 9 February 2020

Please cite this article as: Mazzaglia, A., Legarová, V., Giaquinta, R., Lanza, C.M., Restuccia, C., The influence of almond flour, inulin and whey protein on the sensory and microbiological quality of goat milk yogurt, LWT - Food Science and Technology (2020), doi: https://doi.org/10.1016/j.lwt.2020.109138. This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. 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. © 2020 Published by Elsevier Ltd.

1

The Influence of Almond Flour, Inulin and Whey Protein on the Sensory and Microbiological Quality

2

of Goat Milk Yogurt

3 Agata Mazzaglia1*, Veronika Legarová2, Rossella Giaquinta3, Carmela Maria Lanza3, Cristina Restuccia1

4 5

1

6

Department of Agricultural, Food and Environment, University of Catania, via Santa Sofia 98, 95123 Catania, Italy

7 8

2

9

3

Department of Quality of Agricultural Products, Kamycka 129, 165 21 Prague 6, Suchdol, Czech Republic Trees and Timber Institute, National Research Council - ITALY (CNR - IVALSA), via Pietro Gaifami 18, 95126 Catania, Italy

10 11 12 13 14 15 16 17 18 19 20 21 22 23 24

*

25

Dr. Agata Mazzaglia Ph.D

26

Department of Agricultural, Food and Environment, University of Catania, via Santa Sofia 98, 95123

27

Catania, Italy

28

Phone: 39 0957580220; Fax: 39 095 7141960: E-mail: [email protected] (A. Mazzaglia).

Corresponding author:

1

29

Abstract

30 31

A set of six formulations of goat yogurt added with mix of starter (Lactobacillus bulgaricus and

32

Streptococcus thermophilus), inulin, almond flour and whey protein have been evaluated in Italy and Czech

33

Republic by microbiological and sensory analyses. The yogurt were prepared in the two laboratories

34

involved in testing using the same raw materials found on the Italian market and provided to Czech

35

researchers. The panel of each country separately defined sensory profiles by applying the same

36

methodology. The results had shown a different discrimination of samples: the Italian panel, habitual

37

consumer of goat dairy products, discriminated samples for goat yogurt aroma and flavor; the Czech panel,

38

used to consume fermented milk, discriminated samples for acid descriptor. For both the panels, the addition

39

of inulin was assessed as irrelevant, while the addition of whey was assessed as relevant. The addition of

40

prebiotics, almond flour and inulin, did not affect microbial counts.

41 42

Keywords: sensory profile, goaty aroma, prebiotics, Italian panel, Czech panel.

43 44 45 46 47 48 49 50 51 52 53 54 55 56 2

57

1. Introduction

58 59

Different types of traditional and industrial fermented milk products are manufactured throughout the world,

60

mainly from cow milk. However, the use of goat milk is increasingly, becoming an opportunity to diversify

61

the dairy market with the development of fermented products characterized by undoubted benefits: higher

62

digestibility and lower allergenic properties compared to cow milk (Barrionuevo, Alferez, Lopez Aliaga,

63

Sanz Sampelayo, & Campos, 2002; Martín-Diana, Janer, Pelaez, & Requena, 2003; Milani & Wendorff,

64

2011). Responding well to the interest for health food and novel dairy products, goat milk presents higher

65

content of short chain fatty acids, zinc, iron, magnesium and antibacterial compounds compared to cow milk

66

(Farnsworth et al., 2007; Slacanac et al., 2010). The absence of carotenes (vitamin A) entails those goat dairy

67

products to have a particularly white color that, as appearance feature, is a positive descriptor because it’s

68

perceived by the consumers as an indicator of healthiness and freshness (Spence & Piqueras-Fiszma, 2016).

69

Goat milk significantly differs from cow milk in fatty acid content, being much higher the percentages of

70

many saturated fatty acids (C4-C16) and linolenic acid (C18:2) and secondly of stearic and oleic acid

71

(Young, Gupta, & Sadooghy-Saraby, 2012). With respect to cow milk, the fat component of goat milk

72

presents smaller globules with a protective breakable membrane: this characteristic determines a marked

73

sensitivity to lipolysis, phenomenon which splits the fat globules releasing free fatty acids (BCFAs), like 4-

74

methyloctanoic acid, which are easily attacked by lipase producing the typical unlike smell and taste (goaty)

75

(Young et al., 2012), that sensorially limits the market opportunities for goat milk products. This limitation is

76

particularly important where consumers are allergic or otherwise intolerant to cow milk but not to goat milk

77

(Haenlein, 2004).

78

A further problem is the lower percentage of casein, determinant for the dairy products consistency, that

79

results in lower consistency of hardly purged cheese and lower viscosity of goat milk yogurt compared to

80

cow yogurt. There are numerous scientific researches to improve the rheological characteristics of different

81

dairy products: for example in the production of camel milk yogurt serious limitation of no or weak gel

82

formation was overcome adding gelatin (0-1.25%) (Mudgil, Jumah, Ahmad, Hamed, & Maqsood, 2018).

83

In addition, goat milk itself may be a suitable vehicle for delivering probiotics and prebiotics to humans,

84

further enhancing its health promoting value (Costa et al., 2015; De Souza Oliveira, Perego, De Oliveira, & 3

85

Converti, 2011; Meyer, Bayarri, Tarrega, & Costell, 2011; Mituniewicz-Małek, Ziarno, & Dmytrów, 2014;

86

Palframan, Gibson, & Rastall, 2003; Srisuvor, Chinprahast, Prakitchaiwattana, & Subhimaros, 2013).

87

Prebiotic requirements are well satisfied from inulin, a low calories carbohydrate (100 kcal/100 g), almost

88

exclusively consisting of units b- (2-1) fructosyl-fructose, obtained at industrial level from the chicory plant

89

(Cichorium intybus) (Balthazar et al., 2016; Gibson, 1999). Similarly to inulin and fructo-oligo-saccharides,

90

almond seeds (Prunus amygdalus communis) have been recently proved to possess dietary fiber function

91

(Ellis et al., 2004), with potential prebiotic properties. The soluble fiber (14.3% of weight) of almond, not

92

digested in the stomach but highly fermentable in the large intestine without production of intestinal gas,

93

improves the digestive health (Drake, Chen, Tamarapu, & Leenanon, 2000). The almond seed skins present

94

lipids favoring the development and the significant increase of intestinal bacteria such as Bifidus bacteria,

95

Clostridium and Eubacterium rectal coccoides (Mandalari, Nueno-Palop, Bisignano, Wickham, & Narbad,

96

2008; Palframan et al., 2003) even if the skin may hinder the bio accessibility of lipids (Ellis et al., 2004).

97

The almonds have been included in the recommendations of the Dietary Guidelines for Americans (Slawson,

98

Fitzgerald & Morgan, 2013) thanks to their nutritional benefits: intake of proteins (22%), essential fatty acids

99

(not containing cholesterol), minerals (manganese, potassium, magnesium, calcium, copper, phosphorus),

100

folate, phytosterols, and vitamins (especially vitamin B2 and vitamin E) (www.crea.gov.it.). Furthermore the

101

carbohydrate content of almonds (20%, of which only 5% are simple sugars) can help to reduce post-prandial

102

glycemic peak.

103

The popularity of dairy products fortified with prebiotics and probiotics continues to increase as consumers

104

desire flavorful foods that, at the same time, are able to fulfill their health needs (Allgeyer, Miller, & Lee,

105

2010; Senaka Ranadheera, Evans, Adams, & Baines, 2012). Therefore, in addition to the nutritional benefits,

106

it is essential to evaluate the sensory characteristics of these products.

107

Milk caprine products are less appreciated by consumers respect to traditional milk cow products (Güler-

108

Akin & Akin, 2007; Serhan, Mattar, & Debs, 2016) especially by inexperienced goat milk consumers, while

109

those who have experience of goat milk have shown uncertainty on its assessment. Most of our food choices

110

are based on learning (toxicity, nutritional values, etc.) but most of this learning is done by cultural

111

transmission (Rozin, 2005). When products are similar to each other unfamiliar to one culture, cross-cultural

4

112

disagreements are observed (Chung & Chung, 2007). Inspired by this statement, do people of different

113

culture give the same characteristics to the same products?

114

The objective of this research was the sensory and microbiological evaluation of goat yogurt added of three

115

ingredients: almond flour, as a reducer of unpalatable taste and aroma (goaty), whey protein and inulin as

116

modifier of the texture of dairy products. Moreover, the influence of the panel nationality on the sensory

117

evaluation was evaluated within a Community Project Erasmus between the Di3A of University of Catania

118

and the Department of Agricultural and Food Quality of the Czech University of Life Sciences in Prague,

119

two cultures with important differences in dairy product consumption habits.

120 121

2. Material and Methods

122 123

2.1 Preparation of yogurt samples

124 125

For the present study, 6 samples of yogurt were prepared in the two laboratories involved in sensory testing

126

using raw materials (milk, starter cultures, almond flour and inulin) found on the Italian market (Table 1) and

127

provided to the Czech University. The different formulations of yogurt were obtained from goat milk added

128

with 0.72% of a commercial starter culture of Lactobacillus bulgaricus and Streptococcus thermophilus. The

129

samples were placed in a thermostat at a temperature of 42.5 ± 0.5 °C for 6 h until obtaining a compact

130

consistence of the yogurt. This procedure was applied to white yogurt, used as control, while the other

131

experimental samples were obtained by the supplementary addition of 2.8 g/100 mL inulin and 3 g/100 mL

132

almond flour, the latter previously toasted in the microwave (grill function) for 6 min at 1000 W in order to

133

reduce the humidity and further the microbial load (in the legal limits).

134 135

Table 1. List of the analyzed yogurt samples.

136 137

The use of goat milk for the production of fermented milk must necessarily include a phase of fortification,

138

aimed at improving the characteristics of the clot. This, in fact, usually occurs because goat milk has a

139

slightly lower casein content compared to cow milk, with a very low proportion or absence of αs1-casein, and 5

140

a higher degree of casein micelle dispersion (Martín-Diana, Janer, Pelaez, & Requena, 2003). Therefore, an

141

additional experimental trial, including the addition of 10 g/100 mL whey protein to the white yogurt,

142

almond flour-added yogurt and inulin-added yogurt was also considered.

143 144

2.2 Sensory evaluation

145 146

The sensory profile of the samples (UNI 10957:2003) was defined by two panels (Italian and Czech) to study

147

the influence of their different provenience country and consequent dietary habits.

148

The Italian panel consisted of 12 trained judges (six female and six male, 24-40 years old), recruited among

149

the students and the staff of Di3A (University of Catania). To be experienced on the products and develop a

150

common lexicon (Cayot, Schenker, Houze, Sulmont-Rosse, & Colas, 2008; Coggins, Schilling, Kumari, &

151

Gerrard, 2008; Drake et al., 2000), the judges have evaluated several commercial goat yogurts, to finally

152

generate the descriptors among which, according to the citation frequency fixed at 50% (Lawless &

153

Heymann, 2010), 16 attributes were selected (Table 2).

154 155

Table 2. List of evaluated sensory attributes, definitions and corresponding standards.

156 157

The Czech panel was constituted by 12 judges (seven female and five male, 24-40 years old), recruited

158

among the students of Czech University of Life Sciences Prague who had attended and passed the

159

examination of sensory analysis based on their interest, availability and consumption of plain goat yogurt.

160

The panel was trained for 72 h over a 6 month time period (3h/week); there were a total of 24 training

161

sessions each lasting approximately 1h in duration. These Czech judges used for the sensory evaluation the

162

attributes chosen by the Italian panel. In Italy and in Czech Republic the evaluation of the sensory profile of

163

each sample was carried out in sensory laboratory (UNI EN ISO 8589:2014), and the testing activity was

164

identically organized.

165

The yogurt samples were kept at room temperature (22 ± 2°C). One hour prior to the experiment, 30g of each

166

sample was weighted into the serving container, which then was immediately closed. The samples were

167

coded with 3-digit random numbers. Judges had access to water and unsalted crackers throughout the 6

168

evaluation. Samples were analyzed in triplicate with randomized order of presentation between judges and

169

sessions, by assigning a score between 1 (absence of sensation) and 9 (extremely intense sensation) to each

170

descriptor. Only the sensory laboratory booths of Di3A of the Faculty of Agriculture, University of Catania,

171

were equipped with specific software for the acquisition and processing of sensory data (FIZZ Biosystèmes).

172 173

2.3 Microbiological analyses

174 175

Yogurt samples were serially diluted with quarter-strength Ringer solution (OXOID, BR0052, Basingstoke,

176

UK) and plated on the following media: De Man, Rogosa, Sharpe (MRS) agar medium at pH 5.6 (OXOID,

177

CM0361) with cycloheximide 0.1% solution (OXOID, SR0222), for the enumeration of lactobacilli; M17

178

agar medium (OXOID; CM0785) with cycloheximide 0.1% solution for the enumeration of Streptococcus

179

thermophilus; Sabouraud Dextrose Agar (SDA, OXOID, CM0041) supplemented with 0.1 g/L

180

chloramphenicol (SR0078, Oxoid), for the enumerations of yeast and molds. MRS and M17 plates were

181

incubated at 32°C for 24-48 h; SDA plates were incubated at 25 °C for 48-72 h. Microbiological counts were

182

performed in triplicate and expressed as average log10 cfu/g sample.

183 184

2.4 Statistical analysis

185 186

The sensory data for each attribute were submitted to ANOVA with the following effects: samples (S),

187

judges (J), replications (R). The microbiological data were detected by the one-way Analysis of the Variance

188

(ANOVA). ANOVA was utilized to analyze sensory and microbiological data at the 5% level of significance

189

(p ≤ 0.05). Data analysis was carried out by statistic software Statgraphics® Centurion XVI (Statpoint

190

Technologies, Inc.).

191

The average sensory data were also examined by Principal Component Analysis (PCA) to interpret

192

differences among yogurt samples using The Unscrambler® statistical software package version 9.8 (Camo

193

As, Trondheim, Norway).

194 195

3. Results and Discussion 7

196

3.1 Sensory profiles

197 198

The results of the sensory analyses are shown in Table 3. The results proved that the yogurt samples

199

evaluated by Italian judges are significantly different for the attributes white colour, brightness, creaminess,

200

goat yogurt odour, almond odour and flavour, off-odour and off-flavour. The F-values for judges (J) were

201

significant different for all attributes except for almond odour and flavour; the F-value for replications (R)

202

were not significant different for all attributes except for creaminess and off-flavour

203

The yogurt samples evaluated by Czech panel are significantly different for the attributes creaminess,

204

almond odour and flavour, sour, sweet, off-flavour and overall.

205 206

Table 3. Influence of samples (6), judges (12) and replications (3) on the significant sensory attributes.

207 208

The judge effect (J) was significant different for all attributes except for sweet, while the replication effect

209

(R) was not significant different for all attributes except sour and off-flavour.

210

These results indicated that the mean scores given by the two panels (Italian and Czech) for each attribute of

211

yogurt samples were satisfactory estimates of their sensory profiles.

212

The mean data of the significant attributes were submitted to Principal Component Analysis (PCA) in order

213

to identify, on a multidimensional space, the importance of various attributes in discriminating among

214

samples.

215

The Bi-plot of the yogurt samples evaluated by the Italian panel is displayed in Fig. 1. The variance

216

explained by the first two principal components was 96%. The Bi-plot proved that the samples were well

217

separated in the space, the first component (PC1) (explained variance 77%) distinguished the samples A, B,

218

C from D, E and F, while the second component (PC2) (explained variance 19%) distinguished the samples

219

without almond from those with almond (B and E). The sample B, in the first quadrant, was characterized by

220

the odour and flavour of almond, off-odour and off-flavour. The addition of almond flour had a negative

221

effect, since it developed off-odour and off-flavour and didn’t contribute to decrease the unwanted goat

222

odour.

8

223

The samples A and C, grouped in the second quadrant, were characterized by the attributes white colour,

224

brightness and goat yogurt odour, highlighting how the inulin didn’t affect the sensory characteristics of

225

yogurt, while the samples D (milk + starter + whey protein) and F (milk + starter + whey protein + inulin),

226

grouped in the third quadrant, were not characterized by any attributes. The sample E, in the fourth quadrant,

227

was characterized by the descriptor creaminess. The addition of whey protein reduced the intensity of the

228

odor and flavor of almond; it had also a positive effect, since it reduced the intensity of off-odour and off-

229

flavour and highlighted the creaminess, thus improving the consistency of the yogurt.

230 231

Figure 1. Loading plot of yoghurt samples evaluated by Italian panel

232 233

The Bi-plot of the yogurt samples evaluated by the Czech panel is shown in Fig. 2 and the variance

234

explained by the first two principal components was 96%. The six significant attributes well separated the

235

samples in the space. The first component (PC1) (explained variance 55%) distinguished the samples B, D

236

and E from A, C and F, while the second component (PC2) (explained variance 41%) distinguished the

237

samples A, B and C from D, E and F.

238

The samples D, E and F, grouped in the first quadrant, were characterized by the attributes creaminess, sweet

239

and overall. For the sample E, evaluated by the Czech judges, the addition of whey protein reduced the odor

240

and flavour of almond. The sample B (goat milk + starter + almond), in the second quadrant, was

241

characterized by odour and flavour of almond and off-flavour, confirming that the addition of almond flour

242

develops unpleasant odour and flavour. The samples A and C, grouped in the third quadrant, were

243

characterized only by the sour descriptor. This result confirms that the addition of inulin is irrelevant on the

244

sensory characteristics of yogurt.

245 246

Figure 2. Loading plot of yoghurt samples evaluated by Czech panel

247 248

Among the samples, the Italian judges discriminated the odour and flavour of goat because they are habitual

249

consumers of goat products (i.e. cheese and yogurt) produced in some areas of Italy. New tend shows that

9

250

sensory profile variability between countries is of the same order of magnitude than variability within

251

country (Pages, Bertrand, Alì, Husson, & Le, 2007).

252

The Czech judges, accustomed to the consumption of fermented milk with a characteristic sour taste,

253

discriminated samples on the basis of acid and sweet descriptors but not on the basis of the odour and flavour

254

of goat, probably for the poor presence of goat dairy products on their market and/or for their high cost. In

255

fact, the perception of a sensory characteristic is influenced by the level of familiarity with that characteristic

256

(i.e. odour/flavour of goat). Familiarity for products with similar sensory characteristics can provide a

257

context for newly developed foods, signaling their palatability and safety, thus increasing their liking and

258

purchase (Borgogno, Corazzin, Saccà, Bovolenta, & Piasentier, 2015).

259 260

3.2 Microbiological counts

261 262

The results of the viable counts of the starter bacteria group (composed of S. thermophilus and L. bulgaricus)

263

in goat yogurt containing or not inulin, almond flour and whey protein during refrigerated storage are

264

presented in Table 4. The counts of starter bacteria group at the first day of storage were approximately 9 log

265

cfu/mL for all samples. After 10 days of refrigerated storage, a decrease of starter counts occurred, with

266

slight differences among samples. In particular, within samples without whey addition, the one with inulin

267

had the highest count (8 log cfu/mL) while the addition of almond flour caused a more marked reduction in

268

bacterial viability (7 log cfu/mL).

269 270

Table 4. Viable counts (log cfu/mL) of the starter bacteria group (S. thermophilus and L. bulgaricus) in goat

271

yogurt samples.

272 273

Yogurt samples added with whey showed, in general, higher counts of starter bacteria, ranging from 7 log

274

cfu/mL of almond-added sample to 8.78 log cfu/mL of white yogurt. After 20 days of refrigerated storage,

275

the starter bacterial counts in yogurt samples without whey addition dropped to approximately 6 and 6.5 log

276

cfu/mL, respectively in goat yogurt containing almond flour and in the white or inulin-added samples.

277

Differently, the addition of whey maintained the viability of starter cultures, with count values ranging from 10

278

6.5 log cfu/mL in almond-added sample to 8.2 log cfu/mL in white sample. Overall, the starter bacteria

279

group presented a linear decrease in counts over time in all yogurt formulations; however, these counts were

280

higher in yogurts containing whey, especially from the 10th to 20th day of storage. Decreases (1 – 2 log cycle)

281

in starter bacteria counts is an expected behavior during yogurt storage (Balthazar et al., 2016; Varga, Süle &

282

Nagy, 2014). However, higher decrease values detected in yogurt samples without whey addition may

283

suggest that whey proteins favored the maintenance of starter lactic acid bacteria survival during storage.

284

Previous results, mainly on bovine milk yogurt, obtained by supplementation of milk by whey proteins are

285

contradictory. Some authors did not prove any difference in the growth of probiotic lactobacilli in milk with

286

added whey protein supplements (Martín-Diana et al., 2003). Others (Božanić, Tratnik, Herceg, & Maric,

287

2004; Dave & Shah, 1998) added 2% WPC (whey protein concentrate) to improve the growth of

288

microorganism, so they obtained positive effects on the viable counts of S. thermophilus in yogurt containing

289

bifidobacteria. After 24 h of fermentation, they found viable counts of S. thermophilus as 8.66 log cfu/g in

290

yogurt containing 2% WPC which are similar to the results reported by Akalin, Gong, Unal, & Fenderva

291

(2007). Increase in the viability of S. thermophilus was also determined in probiotic-fermented milks

292

supplemented with WPC (Lucas, Sodini, Monnet, Jolivet, & Corriue, 2004; Martín-Diana et al., 2003). WPC

293

was also shown to increase the growth and viability of Bifidobacterium species in goat’s milk, and the

294

content of WPC added to milk was found to be significant (Božanič & Tratnik, 2001; Martín-Diana et al.,

295

2003). McComas & Gilliland (2003) reported that Bifidobacterium longum S9 was significantly stimulated

296

by whey protein hydrolysate in yogurt. Similar results were obtained by Janer, Pelanez, & Requena (2003)

297

with added Bifidobacterium lactis in milk supplemented with WPC.

298

Conversely, the addition of inulin to the goat yogurt did not positively influence starter bacteria viability,

299

with respect to the relative white yogurt samples. This is in contrast with the results of De Souza Oliveira,

300

Perego, Oliveira, & Converti (2012) who pointed out a generalized stimulation of the overall metabolism of

301

lactic acid bacteria induced by inulin, as the likely result of fructose release from its partial hydrolysis and

302

subsequent metabolization as an additional carbon and energy source (De Souza Oliveira, Perego, De

303

Oliveira, & Converti, 2011).

304

With reference to fungal count, there was no mould or yeast presence in all goat yoghurt samples tested in

305

this study, at any sampling time throughout the storage period, indicating that the product shelf life was not 11

306

limited by yeasts or molds spoilage and that the microwave heat treatment of almond flour was effective at

307

reducing fungal contamination.

308 309

4. Conclusion

310 311

The perceived complexity of new food products plays a crucial role in their introduction to the market.

312

This research, even though it had not fully achieved the health and sensory aims, has allowed to conclude

313

that for a food product, the sensory aspect is determined both by the familiarity of the judges with the raw

314

material (e.g. goat milk) and with the products derived from it, as cheese or yoghurt.

315

To be habitual consumers of goat products leads to better discrimination of the typical descriptors of goat

316

milk, while the habitual consumers of fermented milk, products characterized by a sour taste and a fluid

317

consistency, discriminate better these attributes.

318

Inulin and almond had no effects on the lactic bacteria growth or on the reduction of odor and flavor goat.

319

The hypothesized positive effect of the addition of almond flour was useless by its high lipid content which

320

conferred off-odor and off-flavor to yogurt. In fact, both panels perceived off-odour and off-flavour in the

321

yogurt samples added with almond flour. Any addition of almond should anticipate its degreasing. Inulin and

322

almond, ingredients that have not decreased the odour and flavour of goaty, could be added in the definitive

323

formulation for their nutritional intake of fiber and protein respectively.

324

The addition of serum whey (a low-cost dairy product) has modified the rheological properties of the product

325

by increasing its creaminess and it had a positive effect on the reduction of aroma and flavor goat, making

326

the goat yogurt less unpleasant to the Czech panel increasing its overall score, then a low-cost dairy product

327

by-product can be added.

328

Moreover, this research concerns only the sensory profile. It is interesting to study both descriptive and

329

hedonic point of views.

330 331

REFERENCES

12

332

Akalin, A. S., Gong, S., Unal, G., & Fenderva, S. (2007). Effects of fructooligosaccharide and whey protein

333

concentrate on the viability of starter culture in reduced-fat probiotic yogurt during storage. Journal of

334

Food Science, 72(7), 222–227.

335 336

Allgeyer, L. C., Miller, M. J., & Lee, S. Y. (2010).Sensory and microbiological quality of yogurt drinks with prebiotics and probiotic. Journal of Dairy Science, 93(10), 4471–4479.

337

Balthazar, C. F., Conte junior, C. A., Moraes, J., Costa, M. P., Raices, R. S. L., Franco, R. M., Cruz, A. G.,

338

& Silva, A. C. O. (2016). Physicochemical evaluation of sheep milk yogurts containing different levels of

339

inulin. Journal of Dairy Science, 99(6), 4160–4168.

340

Barrionuevo, M., Alferez, M. J. M., Lopez Aliaga, I., Sanz Sampelayo, M. R., & Campos, M. S.

341

(2002).Beneficial effect of goat milk on nutritive utilization of iron and copper in malabsorption

342

syndrome. Journal of Dairy Science, 85(3), 657–664.

343 344 345 346

Borgogno, M., Corazzin, M., Saccà, E., Bovolenta, S., & Piasentier, E. (2015).Influence of familiarity with goat meat on liking and preference for capretto and chevon. Meat Science, 106, 69–77. Božanič, R., & Tratnik, L. (2001).Quality of cow’s and goat’s fermented bifido milk during storage. Food Technology and Biotechnology, 39(2), 109–114.

347

Božanić, R., Tratnik, L. J., Herceg, Z., & Maric, O. (2004). The influence of milk powder, whey protein

348

concentrate and inulin on the quality of cow and goat acidophilus milk. Acta Alimentaria, 33(4), 337–

349

346.

350 351

Cayot, P., Schenker, F., Houze, G., Sulmont-Rosse, C., & Colas B. (2008). Creaminess in relation to consistency and particle size in stirred fat-free yogurt. International Dairy Journal, 18, 303–311.

352

Chung, L., & Chung, S. J. (2007). Cross-cultural comparison among the sensory characteristics of fermented

353

soybean using Korean and Japanese Descriptive analysis panels. Journal of Food Science, 72(9), S676–

354

S688.

355 356

Coggins, P. C., Schilling, M. W., Kumari, S., & Gerrard, P. D. (2008). Development of a sensory lexicon for conventional milk yogurt in the United States. Journal of Sensory Studies, 23, 671–687.

357

Costa, M. P., Frasao, B. S., Silva, A. C. O., Freitas, M. Q., Franco, R. M., & Conte-Junior, C. A. (2015).

358

Cupuasu (Theobroma grandiflorum) pulp, probiotic, and prebiotic: Influence on color, apparent viscosity,

359

and texture of goat milk yogurts. Journal of Dairy Science, 98, 5995–6003. 13

360 361

Dave, R., & Shah, N. P. (1998).Ingredient supplementation effects on viability of probiotic bacteria in yogurt. Journal of Dairy Science, 81(11), 2804–2816.

362

De Souza Oliveira, R. P., Perego, P., De Oliveira, M. N., & Converti, A. (2011). Effect of inulin as a

363

prebiotic to improve growth and counts of a probiotic cocktail in fermented skim milk. LWT – Food

364

Science and Technology, 44, 520–523.

365

De Souza Oliveira, R. P. S., Perego, P., Oliveira, M. N., & Converti, A. (2012). Growth, organic acids

366

profile and sugar metabolism of Bifidobacterium lactis in co-culture with Streptococcus thermophilus:

367

The inulin effect. Food Research International, 48(1), 21–27.

368 369

Drake, M. A., Chen, X. Q., Tamarapu, S., & Leenanon, B. (2000). Soy protein fortification affects sensory chemical and microbiological properties of dairy yogurts. Journal of Food Science, 65, 1244–1247.

370

Ellis, P. R., Kendall, C. W. C., Ren, Y., Parker, C., Pacy, J. F., Waldron, K. W., & Jenkins, D. J. A. (2004).

371

Role of cell walls in the bioaccessibility of lipids in almond seeds. American Journal of Clinical

372

Nutrition, 80(3), 604–613.

373

Farnsworth, E. R., Mainville, I., Desjardins, M. P., Gardner, N., Fliss, I., & Champagne, C. (2007). Growth

374

of probiotic bacteria and bifidobacteria in a soy yogurt formulation. International Journal of Food

375

Microbiology, 116, 174–181.

376

Food composition tables. Available from: http//:www.crea.gov.it. 4 february 2019

377

Gibson, G. R. (1999). Dietary modulation of the human gut microflora using the prebiotics oligofructose and

378

inulin. Journal of Nutrition, 129(7 suppl), 1438S–1441S.

379

Güler-Akin, M. B., & Akin, M. S. (2007). Effect of cysteine and different incubation temperatures on the

380

microflora, chemical composition and sensory characteristics of bio yogurt made from goat’s milk. Food

381

Chemistry, 100, 788–793.

382

Haenlein, G. F. W. (2004). Goat milk in human nutrition. Small Ruminant Research, 51(2), 155–163.

383

Janer, C., Pelanez, C., & Requena, T. (2004). Caseinomacropeptide and whey protein concentrate enhance

384 385 386

Bifidobacterium lactis growth in milk. Food Chemistry, 86(2), 263–267. Lawless, H. T., & Heymann, H. (2010). Sensory evaluation of food: Principles and practices (2nd ed.). New York, Springer Science+Business Media, LLC.

14

387

Lucas, A., Sodini, I., Monnet, C., Jolivet, P., & Corriue, G. (2004). Probiotic cell counts and acidification in

388

fermented milks supplemented with milk protein hydrolysates. International Dairy Journal, 14(1), 47–53.

389

Mandalari, G., Nueno-Palop, C., Bisignano, G., Wickham, M. S. J., & Narbad, A. (2008). Potential prebiotic

390

properties of almond (Amygdalus communis L.) seeds. Applied and Environmental Microbiology, 74(14),

391

4264–4270.

392 393 394 395 396 397 398 399

Martín-Diana, A. B., Janer, C., Pelaez, C., & Requena, T. (2003). Development of a fermented goat’s milk containing probiotic bacteria. International Dairy Journal, 13(10), 827–833. McComas, K. A., & Gilliland, S. E. (2003). Growth of probiotic and traditional yogurt cultures in milk supplemented with whey protein hydrolysate. Journal of Food Science, 68(6), 2090–2095. Meyer, D., Bayarri, S., Tarrega, A., & Costell, E. (2011). Inulin as texture modifier in dairy products. Food Hydrocolloids, 25, 1881–1890. Milani, F. X., & Wendorff, W. L. (2011). Goat and sheep milk products in the United States (USA). Small Ruminant Research, 101, 134–139.

400

Mituniewicz-Małek, A., Ziarno, M., & Dmytrów, I. (2014). Short communication: Incorporation of inulin

401

and transglutaminase in fermented goat milk containing probiotic bacteria. Journal of Dairy Science, 97,

402

3332–3338.

403

Mudgil, P., Jumah, B., Ahmad, M., Hamed, F., & Maqsood, S. (2018). Rheological, micro-structural and

404

sensorial properties of camel milk yogurt as influenced by gelatin. LWT – Food Science and Technology,

405

98, 646-653.

406 407 408 409 410 411

Pages, J., Bertrand, C., Alì, R., Husson, F., & Le, S. (2007). Sensory analysis comparison of eight biscuits French and Pakistani panels. Journal of Sensory Studies, 22, 665–686. Palframan, R., Gibson, G. R., & Rastall, R. A. (2003). Development of a quantitative tool for the comparison of the prebiotic effect of dietary oligosaccharides. Letters in Applied Microbiology, 37, 281–284. Rozin, P. (2005). The meaning of food in our lives: a cross cultural perspective on eating and well-being. Journal of Nutrition Education and Behavior, 37(Suppl. 2), S107–S512.

412

Senaka Ranadheera, C., Evans, C. A., Adams, M. C., & Baines, S. K. (2012). Probiotic viability and

413

physico-chemical and sensory properties of plain and stirred fruit yogurts made from goat’s milk. Food

414

Chemistry, 135(3), 1411–1418. 15

415

Serhan, M., Mattar, J., & Debs, L. (2016). Concentrate yogurt (Labeneh) made of a mixture of goats’milk

416

and cows’milk: Physicochemical, microbiological and sensory analysis. Small Ruminant Research, 138,

417

46–52.

418 419

Slacanac, V., Bozanic, R., Hardi, J., Rezessyne Szabo, J., Luca, M., & Krstanovic, V. (2010). Nutritional and therapeutic value of fermented caprine milk. International Journal of Dairy Technology, 63(2), 171–189.

420

Slawson, D. L., Fitzgerald, N., & Morgan, K. T. (2013). Position of the Academy of Nutrition and Dietetics:

421

the role of nutrition in health promotion and chronic disease prevention. Journal of the Academy of

422

Nutrition and Dietetics, 113(7), 972-9.

423

Spence, C., & Piqueras-Fiszma, B. (2016). Food color and its impact on taste/flavor perception. In:

424

Multisensory Flavor Perception: From Fundamental Neuroscience through to the Marketplace / Piqueras-

425

Fiszman B, Spence C, Amsterdam: Elsevier Inc. Academic Press (Woodhead Publishing Series in Food

426

Science, Technology and Nutrition), 107–132.

427

Srisuvor, N., Chinprahast, N., Prakitchaiwattana, C., & Subhimaros, S. (2013). Effects of inulin and

428

polydextrose on physicochemical and sensory properties of low-fat set yoghurt with probiotic-cultured

429

banana purée. LWT – Food Science and Technology, 51(1), 30–36.

430 431 432 433

UNI 10957:2003. Sensory Analysis – Method for Establishing a Sensory Profile in Foodstuffs and Beverage. Milan, Italy: Italian National Agency for Standardization. UNI EN ISO 8589:2014. Sensory analysis – General guidance for the design of test rooms. Milan, Italy: Italian National Agency for Standardization.

434

Varga, L., Süle, J., & Nagy, P. (2014). Short communication: Survival of the characteristic microbiota in

435

probiotic fermented camel, cow, goat, and sheep milks during refrigerated storage. Journal of Dairy

436

Science, 97(4), 2039–2044.

437 438

Young, O. A., Gupta, R. B., & Sadooghy-Saraby, S. (2012). Effects of cyclodextrins on the flavor of goat milk and its yogurt, Journal of Food Science, 77(22), 122–127.

16

Figure captions

Figure 1. Loading plot of yoghurt samples evaluated by Italian panel Figure 2. Loading plot of yoghurt samples evaluated by Czech panel

Table 1. List of the analyzed yogurt samples. Samples

1

Formulation of the samples

A

Goat milk1+starter2 (0.72%)

B

Goat milk+starter (0.72%)+almond flour3 (3%)

C

Goat milk+starter(0.72%)+inulin4 (2.8%)

D

Goat milk+starter (0.72%)+whey protein5 (10%)

E

Goat milk+starter (0.72%)+whey protein (10%)+ almond flour (3%)

F

Goat milk+starter (0.72%)+whey protein (10%)+inulin (2.8%)

Whole goat milk UHT Amalattea s.r.l. (Italy); 2Lyophilized ferments (Streptococcus termophilus and Lactobacillus bulgaricus), Insao, s.r.l. (Italy); 3Sicilian natural almond flour Dolcezza di Rumia (Italy); 4Pure instant inulin Naturei REIRE s.r.l. (Italy); 5Resource® whey protein Nestlè S.p.a..

Table 2. List of evaluated sensory attributes, definitions and corresponding standards. Attribute White colour

Description Color of surface (from yellow to withe)

Reference Whole plain yogurt Fattoria Scaldasole s.r.l. Brightness Perceived color of an object indicating the Whole plain yogurt Fattoria relationship between reflected and absorbed Scaldasole s.r.l. light Creaminess Viscosity of the product when the spoon is Whole plain yogurt Fattoria slowly tilted up to 90°C Scaldasole s.r.l. Goat yogurt Characteristics odour of goat yogurt perceived Whole goat yogurt Amalattea odour with the sense of smell s.r.l. Goat cheese Characteristics odour of goat cheese perceived Goat cheese “Tronchetto di capra” odour with the sense of smell Santa Lucia (Galbani) Almond Characteristics odour of almond perceived Sicilian natural almond flour odour with the sense of smell Dolcezze di Rumia Off-odour Unpleasant odour not characteristic of the Sicilian natural almond flour product concerned, perceived through the Dolcezze di Rumia stressed by sense of smell heat (oven 35°C for 7 days) Salt One of the four basic tastes caused by aqueous Yogurt1 added with 3% of sodium solutions of salt compounds perceived on the cloride tongue Sour One of the four basic tastes caused by aqueous Yogurt1 added with 5% citric acid solutions of acid compounds perceived on the tongue Sweet One of the four basic tastes caused by aqueous Yogurt1 added with 10% di solutions of sweet compounds perceived on the sucrose tongue Astringent Sensory perception in the oral cavity that may Yogurt1 added with 1% tartaric include drying sensation, and roughing of the acid oral tissue Goat yogurt Characteristic flavor of goat yogurt perceived Yogurt1 flavor by the sense of smell and mouth with the swallowing Goat cheese Characteristic flavor of goat cheese perceived Goat cheese “Tronchetto di capra” flavor by the sense of smell and mouth with the Santa Lucia (Galbani) swallowing Almond Characteristic flavor of almond perceived by Sicilian natural almond flour flavor the sense of smell and mouth with the Dolcezze di Rumia swallowing Off-flavor Unpleasant flavor not characteristic of the Sicilian natural almond flour product concerned, perceived by the sense of Dolcezze di Rumia stressed by smell and mouth with the swallowing heat (oven 35°C for 7days) Overall Subjective evaluation of the sensory quality of the sample 1 Whole goat yogurt, Amalattea s.r.l.

Table 3. Influence of samples (6), judges (12) and replications (3) on the significant sensory attributes. Italian panel Attribute Sample Judges Replicate Attribute Sample White color 20.70*** 9.57*** 0.62 n.s. Creaminess 39.32*** Brightness 13.66*** 7.53*** 1.88 n.s. Almond odour 30.14*** Creaminess 21.12*** 16.69*** 4.25* Sour 7.09*** Goat yoghurt odour 2.71* 9.30*** 2.08 n.s. Sweet 6.44*** Almond odour 43.95*** 1.24 n.s. 1.40 n.s. Almond flavour 49.34*** Off-odour 4.30** 7.20*** 1.86 n.s. Off-flavour 3.05* Almond flavour 59.14*** 1.25 n.s. 1.73 n.s. Overall 8.28*** Off-flavour 2.50* 11.59*** 3.28* ***significant difference for p ≤ 0.001; **significant difference for p ≤ 0.01; *significant difference for p ≤ 0.05; n.s. no significant difference.

Czech panel Judges Replicate 9.05*** 1.15 n.s. 16.61*** 2.38 n.s. 2.66** 8.07*** 1.26 n.s. 2.82 n.s. 7.80* 0.72 n.s. 2.92** 3.34* 13.41*** 2.23 n.s.

Table 4. Viable counts (log cfu/mL) of the starter bacteria group (S. thermophilus and L. bulgaricus)

in goat yogurt samples. Days of storage B 9.0

Samples C D 9.0 9.0

E 9.0

F 9.0

8.0b

7.0a

8.0b

t0

A 9.0

t10

7.3a* 7.0a

t20

6.5ab 6.0a 6.5ab 7.53c 6.5ab 7.2bc

8.8c

*Values marked with different letters in the same column are significantly different (p ≤ 0.05) according to the LSD multiple comparison test

• • •

It has been reached the possibility to reduce the goaty aroma and flavor often disliked by

consumers Added inulin, almond and whey protein can effectively improve the flavor of the goat milk products To examine from a sensorial point of view, if judges of different nationalities, with a different food culture, evaluate the samples in the same way or not.

Authors contribution sections

All authors have made substantial contributions to all of the following: the conception and design of the study, acquisition of data, analysis and interpretation of data.

Agata Mazzaglia

Conflict of Interest

The authors Agata Mazzaglia, Veronika Legarová, Rossella Giaquinta, Carmela Maria Lanza, Cristina Restuccia have no affiliation with any organization with a direct or indirect financial interest in the subject matter discussed in the manuscript. Agata Mazzaglia