Utilization of Vaccinium meridionale S. pomace as an eco-friendly and functional colorant in Greek-style yogurt.

Greek-style yogurt (GSY) has gained reputation as a healthy food because of its high protein content. Vaccinium meridionale S. is a bilberry with a high content of bioactive phytochemicals, whose vaccinium meridionale pomace (VMP) represents about 20% of the fruit weight. However, this byproduct is normally discarded as waste. In this study, VMP was used as a natural colorant in GSY. Coloring before or after the fermentation process resulted in significant increase in anthocyanins, total phenolics content, antioxidant activity, conjugated linoleic acid, and sensory acceptance. These results indicate that VMP is a potential natural, eco-friendly, and functional colorant to improve the nutritional value of GSY. PRACTICAL APPLICATION: Vaccinium meridionale pomace is a waste product with potential to be utilized as a natural, eco-friendly, and functional colorant to obtain value-added Greek-style yogurt. Besides providing bioactive compounds and natural color, this pomace improves the nutritional value, sensory acceptance, and functional properties of Greek yogurt.

A Cross-Sectional Audit of Nutrition and Health Claims on Dairy Yoghurts in Supermarkets of the Illawarra Region of New South Wales, Australia.

Health and nutrition claims are used by consumers to guide purchasing decisions. In consequence, monitoring and evaluation of such claims to ensure they are accurate and transparent is required. The aim of this study was to investigate the use of nutrition and health claims on dairy-yoghurt products within select Australian supermarkets and assess their compliance with the revised Food Standards Code (FSC). Nutrition, health, and related claims on yoghurt products were assessed in a cross-sectional audit of five supermarkets in the Illawarra region of New South Wales. Claim prevalence, type, and compliance were assessed and products were compared against current rating measures. A total of n = 340 dairy yoghurt products were identified. Most products (97.9%) carried at least one nutrition and/or health claim, with nutrition-content claims (93.9%) the most prevalent. Most products (n = 277) met the nutrient profiling scoring criterion; while 87.9% of products did not carry the health star rating. Almost all claims surveyed (97.4%) were compliant with the FSC. Health and nutrition claims are highly prevalent across yoghurt categories, with the majority of these compliant with regulations. The ambiguity surrounding the wording and context of claims challenges researchers to investigate consumers' interpretations of health messaging within the food environment.

Invited review: Probiotic yogurt quality criteria, regulatory framework, clinical evidence, and analytical aspects.

Yogurt is a milk-based product manufactured by lactic acid fermentation enabled by symbiotic yogurt cultures. Yogurt is largely considered to be a health product, and it is employed to deliver probiotics and prebiotics to the consumer. However, not all yogurts are probiotic, neither are they all functional products. There is increasing demand for health-promoting beverages, which is prompting the dairy industry to develop functional probiotic yogurts to meet the demand. However, there seems to be a scarcity of reviews providing critical information on regulatory frameworks in regions of the world, clinical trial outcomes, and methodological approaches for enumerating multiprobiotic strains in yogurt. This review, relating to functional probiotic yogurt, covers the newest information on the topic for the period mostly between 2014 and 2019. Conformance to regulations is paramount and hence, global regulatory frameworks for probiotic yogurt and prebiotic and nonprebiotic ingredients included in yogurt are reviewed. The paper emphasizes the need for convincing clinical trial outcomes that provide the dairy industry with an opportunity to market products with substantiated beneficial claims. The paper also discusses probiotic strains in functional yogurt, which is required to have population levels above the recommended therapeutic minimum during shelf life. The multiprobiotic species added to yogurt may present challenges relating to methodological and analytical approaches needed to determine viability of each strain contained in such yogurt. Hence, the review also presents the pros and cons of the culture-dependent and culture-independent approaches for the enumeration of probiotic cells in yogurt. The review is arguably valuable to the dairy industry, functional food developers, related scientists, and researchers, as well as policy makers.

Soybean peptides promote yoghurt fermentation and quality.

OBJECTIVES: This research paper was to investigate the influence of soybean peptides addition on viable count of lactic acid bacteria, physicochemical parameters, flavor, and sensory evaluation of yoghurt. RESULTS: The number of fermenting strains (Streptococcus thermophilus + Lactobacillus delbrueckii subsp. bulgaricus) cells in yoghurt (stored at 4 °C for 19 days) added with 0.2% (w/v) of soybean peptides (808.34 Da) reached 1.4 times higher bacterial number than in the control group. A total of 34 volatile substances were detected in this study, while there were 22 volatiles occurred in the control group yoghurt, 30 volatiles were detected in yoghurt added with 0.2% soybean peptides. There was no significant difference in sensory evaluation (p > 0.05) between the yoghurt with and without soybean peptides. CONCLUSIONS: In our study, the addition of soybean peptides (0.2%) can be effective both in maintaining the viable bacterial count and yoghurt quality.

Avaliação físico-química do iogurte de leite de cabra com adição das geleias de abacaxi (Ananas comosus) e noni (Morinda cintrifola L. ) / Physical-chemical evaluation of yoghurt of goat milk with addition of pineapple (Ananas comusus) and noni (Morinda cintrifola L. ) jellies

Objetivou-se elaborar iogurte de leite de cabra com adição das geleias de abacaxi (Ananas comosus) e noni (Morinda citrifolia L.) e avaliar a composição físico-química do produto. Foram preparados cinco tratamentos do iogurte de leite de cabra, adicionados com diferentes concentrações das geleias de abacaxi e noni (0, 0,5, 1,25, 2,5 e 5%) e analisados em triplicata as composições físico-química quanto: acidez titulavel, gordura, pH, cinzas, umidade e lactose. Os resultados foram submetidos a análise estatística de variância (ANOVA) seguido do teste de Tukey a nível de 5% para comparação das médias. Apenas a amostra com 5% das geleias de abacaxi e noni apresentou diferença estatística (p<0,05) na variável gordura, porém assim como os demais parâmetros estavam dentro das normas da legislação estabelecida.

Avaliação físico-química do iogurte de leite de cabra com e sem geleias de abacaxi (Ananas comosus) e banana (Musa spp) / Physico-chemical evaluation of goat's milk yogurt with and without pineapple (Ananas comosus) and banana (Musa spp) jellies

Objetivou-se avaliar a qualidade físico-química dos iogurtes elaborados de leite de cabra com e sem geleias de frutas de abacaxi e banana. Elaborou-se, IN–iogurte de leite de cabra sem adição de geleia de fruta (0%); IA–iogurte com adição de geleia de abacaxi (15 e 20%); IB–iogurte com adição de geleia de banana (15 e 20%), onde avaliou-se os teores de lactose, gordura, cinzas, pH, acidez e umidade, obtendo os resultados 4,3 a 6,3%; 3,8 a 5,5%; 0,5 a 0,6%; 4,29 a 4,38; 0,77 a 0,95g de ácido lático/100g; 78,7 a 88,0%, respectivamente, cuja diferença foi significativa (p<0,05), exceto para o teor de cinzas. Os parâmetros avaliados dos iogurtes, apresentaram-se de acordo com os valores da legislação, contribuindo para a valorização de derivados lácteos caprinos e inovação tecnológica através de um novo produto para o mercado consumidor.

Evaluation of the nutrient content of yogurts: a comprehensive survey of yogurt products in the major UK supermarkets.

OBJECTIVES: To comprehensively survey the sugar and nutrient contents of yogurt products available in UK supermarkets, in particular those marketed to children. DESIGN: A cross-sectional survey of yogurt products available in the UK's supermarkets in November 2016. METHODS: Data were collected from five major online UK supermarkets and a process flow strategy was used to place yogurts into eight categories: children's, dairy alternatives, dessert, drinks, fruit, flavoured, natural/Greek style and organic. A comprehensive database of product information for 921 unique products was created and analysed. RESULTS: The total sugar, fat, protein, calcium and energy contents were highly variable across categories, and the ranges were extremely broad. Although lower than the dessert category, the medians (range) of the total sugar content of children's (10.8 g/100 g (4.8-14.5)), fruit (11.9 g/100 g (4.6-21.3)), flavoured (12.0 g/100 g (0.1-18.8)) and organic (13.1 g/100 g (3.8-16.9)) yogurt products were all well above 10 g/100 g, and represented >45% of total energy. Only two out of 101 children's yogurt and fromage frais products surveyed qualified as low sugar (≤5 g/100 g). Natural/Greek yogurts had dramatically lower sugar contents (5.0 g/100 g (1.6, 9.5), largely lactose) than all other categories. While low-fat (<3 g/100 g) products had less sugar and energy than higher fat yogurts, nonetheless 55% (285 of 518 low-fat yogurts) contained between 10 and 20 g sugar/100 g. Within the children's category, fromage frais had higher protein (5.3 g/100 g (3.3, 8.6) vs 3.2 (2.8, 7.1); p<0.0001) and calcium contents (150 mg/100 g (90, 240) vs 130.5 mg/100 g (114, 258); p=0.0015) than yogurts. CONCLUSIONS: While there is good evidence that yogurt can be beneficial to health, products on the market vary widely in total sugars. Fewer than 9%, and only 2% of the children's, products surveyed were low enough in sugar to earn 'green' in UK front of the pack labelling. Reformulation for the reduction of free sugars in yogurts is warranted.

Use of ß-glucan from spent brewer's yeast as a thickener in skimmed yogurt: Physicochemical, textural, and structural properties related to sensory perception.

Powdered ß-glucan extracted from brewer's yeast (Yestimun, Leiber GmbH, Bramsche, Germany) was incorporated into skimmed-milk yogurt at varying concentrations (0.2-0.8% wt/wt) to investigate its potential application as a thickener. The effect of ß-glucan fortification on the nutritional profile, microstructure, physicochemical properties, and texture of freshly prepared yogurts was investigated. Sensory evaluation was also conducted and was correlated with instrumental analysis. The addition of Yestimun significantly reduced the fermentation time of the yogurt mix from 4 h to 3 h. Scanning electron microscopy revealed that ß-glucan particles formed small spherical clusters within the yogurt matrix. The majority of the physicochemical properties (syneresis, viscosity, color, and titratable acidity) remained unaffected by the incorporation of Yestimun in the recipe. Textural properties showed a gradual increment with increasing ß-glucan concentration. Hardness, total work done, adhesive force, and adhesiveness increased by 19.27, 23.3, 21.53, and 20.76%, respectively, when using the highest amount of Yestimun powder. Sensory analysis (n = 40) indicated that fortifying yogurt with Yestimun at 0.8% (wt/wt) concentration may affect overall acceptance ratings, which was attributed to adverse flavor and aftertaste effects. However, the overall liking score of the yogurt (5.0/9.0) shows potential for commercialization of the product.

Risk assessment of fungal spoilage: A case study of Aspergillus niger on yogurt.

A quantitative risk assessment model of yogurt spoilage by Aspergillus niger was developed based on a stochastic modeling approach for mycelium growth by taking into account the important sources of variability such as time-temperature conditions during the different stages of chill chain and individual spore behavior. Input parameters were fitted to the appropriate distributions and A. niger colony's diameter at each stage of the chill chain was estimated using Monte Carlo simulation. By combining the output of the growth model with the fungus prevalence, that can be estimated by the industry using challenge tests, the risk of spoilage translated to number of yogurt cups in which a visible mycelium of A. niger is being formed at the time of consumption was assessed. The risk assessment output showed that for a batch of 100,000 cups in which the percentage of contaminated cups with A. niger was 1% the predicted numbers (median (5th, 95th percentiles)) of the cups with a visible mycelium at consumption time were 8 (5, 14). For higher percentages of 3, 5 and 10 the predicted numbers (median (5th, 95th percentiles)) of the spoiled cups at consumption time were estimated to be 24 (16, 35), 39 (29, 52) and 80 (64, 94), respectively. The developed model can lead to a more effective risk-based quality management of yogurt and support the decision making in yogurt production.

Microbiological characterization and functionality of set-type yogurt fermented with potential prebiotic substrates Cudrania tricuspidata and Morus alba L. leaf extracts.

The objective of this study was to investigate the effect of 2 plant leaf extracts on fermentation mechanisms and health-promoting activities and their potential as a nutraceutical prebiotics ingredient for application in dairy products. The individual active phenolic compounds in the plant extract-supplemented milk and yogurts were also identified. Compared with control fermentation, the plant extracts significantly increased the growth and acidification rate of Streptococcus thermophilus and Lactobacillus delbrueckii ssp. bulgaricus. In particular, plant extract components, including monosaccharides, formic acid, and hydroxycinnamic acid, such as neo-chlorogenic, chlorogenic, and caffeic acid, together play a stimulatory role and cause this beneficial effect on the growth of yogurt culture bacteria through fermentation. In addition, supplementation with the plant extracts enhanced antioxidant activities with increased total phenolic contents, especially the highest antioxidant activity was observed in yogurt supplemented with Cudrania tricuspidata leaf extract.

Role of milk protein-based products in some quality attributes of goat milk yogurt.

Goat milk yogurts were manufactured with the fortification of 2% (wt/vol) skim goat milk powder (SGMP), sodium caseinate (NaCn), whey protein concentrate (WPC), whey protein isolate (WPI), or yogurt texture improver (YTI). Yogurts were characterized based on compositional, microbiological, and textural properties; volatile flavor components (with gas chromatography); and sensory analyses during storage (21d at 5 °C). Compared with goat milk yogurt made by using SGMP, the other goat milk yogurt variants had higher protein content and lower acidity values. Goat milk yogurts with NaCn and WPC, in particular, had better physical characteristics. Using WPI caused the hardest structure in yogurt, leading to higher syneresis values. Acetaldehyde and ethanol formation increased with the incorporation of WPI, WPC, or YTI to yogurt milk. The tyrosine value especially was higher in the samples with NaCn and YTI than in the samples with WPC and WPI. Counts of Streptococcus thermophilus were higher than the counts of Lactobacillus delbrueckii ssp. bulgaricus, possibly due to a stimulatory effect of milk protein-based ingredients other than SGMP on the growth of S. thermophilus. Yogurt with NaCn was the best accepted among the yogurts. For the parameters used, milk protein-based products such as NaCn or WPC have promising features as suitable ingredients for goat milk yogurt manufacture.

Effects of fermentation with Lactobacillus rhamnosus GG on product quality and fatty acids of goat milk yogurt.

The effect of fermentation with Lactobacillus rhamnosus GG on the product quality of goat milk yogurt using traditional yogurt starter was studied through single-factor experiments and orthogonal experiments. The optimum fermentation condition was evaluated by the titratable acidity of goat milk yogurt, water-retaining capability, sensory score, and texture properties; the fatty acids of the fermented goat milk were determined by a gas chromatograph. Results indicate that high product quality of goat milk yogurt can be obtained and the content of short-chain and medium-chain fatty acids can be decreased significantly when amount of sugar added was 7%, inoculation amount was 3%, the ratio of 3 lactic acid bacteria--Lactobacillus delbrueckii ssp. bulgaricus, Streptococcus thermophilus, and L. rhamnosus GG--was 1:1:3, and fermentation temperature was 42°C.

Polycyclic aromatic hydrocarbons (PAHs) in yogurt samples.

The concentrations and distributions of major polycyclic aromatic hydrocarbons (PAHs) were determined in 20 kinds of yogurt specimens collected from Italian supermarkets using reversed phase high-performance liquid chromatography equipped with fluorescence detection. The method was validated by determination of recovery percentages, precision (repeatability) and sensitivity (limits of detection) with yogurt samples fortified at 0.25, 0.5 and 1 µg/kg concentration levels. The recovery of 13 PAHs, with the exception of naphthalene and acenaphthene, ranged from 61% to 130% and from 60% to 97% at all the levels for yogurts with low (0.1%) and high (3.9%) fat content, respectively. The method is repeatable with relative standard deviation values <20% for all analytes. The results obtained demonstrate that acenaphthene, fluorantene, phenanthrene, anthracene, fluoranthene and pyrene were found in all samples with a similar distribution, but different content when yogurts with low and high fats were compared.

Probiotics in dietary guidelines and clinical recommendations outside the European Union.

Fermented foods have been consumed for centuries across many geographical locales and have traditionally been considered healthy foods, partly because of the live microbes contained in them. The concept of "probiotics" further requires that the microbes be defined and their health effects be demonstrated through human intervention studies or other suitable investigations before marketing with corresponding health messages. Here, we review recommendations for fermented foods and probiotics in several countries outside the EU, focusing on food-based dietary guidelines. We emphasize recommendations on yoghurt and probiotics made by expert bodies. We found that dietary guidelines commonly advocate the consumption of yoghurt or similar products, but specific comments on probiotics are rare. Further, we reviewed guidelines from clinical associations. In general, they acknowledge the beneficial effects of probiotics, but often suggest the need for further research. This is true despite good quality evidence supporting the role of probiotics for certain health effects, such as prevention of eczema in infants, management of side effects from antibiotics and alleviation of functional bowel symptoms. Additional research to support future dietary recommendations should focus on determining effect size, identifying responders and non-responders, clarifying strain-specificity of effects and confirming mechanisms.

Natamycin content and quality evaluation of yoghurt from small- and large-scale brands in Turkey.

In this study, the presence of natamycin and quality parameters of yoghurt samples manufactured by small- and large-scale dairy firms in Turkey were investigated. Physicochemical and microbiological results revealed that, except Lactobacillus bulgaricus and Streptococcus thermophilus counts, the majority of the yoghurts manufactured by small-scale dairy firms were found to be out of the limits. Natamycin was detected in 31 and 2 yoghurt samples from small- and large-scale brands, respectively. The levels of natamycin in small-scale brand yoghurts were higher than those in large-scale brand yoghurts. Of the analysed samples, 42.3% did not comply with the Turkish Food Codex.

Reconstituted yogurt from yogurt cultured milk powder mix has better overall characteristics than reconstituted yogurt from commercial yogurt powder.

For manufacture of commercial yogurt powder, yogurt has to go through a drying process, which substantially lowers the yogurt culture counts, so the potential health benefits of the yogurt culture bacteria are reduced. Also, upon reconstitution, commercial yogurt powder does not taste like yogurt and has an off-flavor. The objective was to study the microbial, physicochemical, and sensory characteristics of reconstituted yogurt from yogurt cultured milk powder (YCMP) mix and reconstituted yogurt from commercial yogurt powder (CYP). The CYP reconstituted yogurt was the control and YCMP mix reconstituted yogurt was the treatment. Microbial and physicochemical characteristics of the CYP reconstituted yogurt and YCMP mix reconstituted yogurt were analyzed daily for the first week and then weekly for a period of 8 wk. Sensory consumer testing of CYP reconstituted yogurt and YCMP mix reconstituted yogurt was conducted with 100 consumers. At 56 d, YCMP mix reconstituted yogurt had 5 log cfu/mL higher counts of Streptococcus thermophilus than the control (CYP reconstituted yogurt). Also, Lactobacillus bulgaricus counts of YCMP mix reconstituted yogurt were 6.55 log cfu/mL at 28 d and were 5.35 log cfu/mL at 56 d, whereas the CYP reconstituted yogurt from 28 d onwards had a count of <10 cfu/mL. The YCMP mix reconstituted yogurt also had significantly higher apparent viscosity and sensory scores for appearance, color, aroma, taste, thickness, overall liking, consumer acceptability, and purchase intent than CYP reconstituted yogurt. Overall, YCMP mix reconstituted yogurt had more desirable characteristics than CYP reconstituted yogurt.

Manufacture and characterization of a yogurt-like beverage made with oat flakes fermented by selected lactic acid bacteria.

This study aimed at investigating the suitability of oat flakes for making functional beverages. Different technological options were assayed, including the amount of flakes, the inoculum of the starter and the addition of enzyme preparations. The beverage containing 25% (wt/wt) of oat flakes and fermented with L. plantarum LP09 was considered optimal on the basis of sensory and technological properties. The enzyme addition favored the growth of the starter, shortened the time needed to reach pH4.2 to ca. 8h, and favored a decrease of the quotient of fermentation. Fermentation increased the polyphenols availability and the antioxidant activity (25 and 70% higher, respectively) and decreased the hydrolysis index in vitro. Sensory analyses showed that fermented oat flakes beverage had the typical features of a yogurt-like beverage, enhancing the overall intensity of odor and flavor compared to the non-fermented control. Selection of proper processing and fermentation condition allowed the obtainment of a beverage with better nutritional and sensory properties.

Physicochemical, microbial, and sensory properties of nanopowdered eggshell-supplemented yogurt during storage.

This study was carried out to investigate the possibility of adding nanopowdered eggshell (NPES) into yogurt to improve the functionality of yogurt and the effects of adding NPES on the physicochemical, microbial, and sensory properties of the products during storage. The pH and mean lactic acid bacteria counts of NPES-added (0.15-0.45%, wt/vol) yogurt ranged from 4.31 to 4.66 and from 6.56 × 10(8) to 8.56 × 10(8)cfu/mL, respectively, whereas these values ranged from 4.13 to 4.44 and 8.46 × 10(8) to 1.39 × 10(9), respectively, for the control samples during storage at 5 °C for 16d, which indicates a prolonged shelf-life with NPES-supplemented yogurt. Color analysis showed that the lightness (L*) and position between red and green (a*) values were not significantly influenced by the addition of NPES. However, the position between yellow and blue (b*) value significantly increased with the addition of the concentration (0.45%, wt/vol) of NPES at d 16 of storage. Sensory evaluation revealed that NPES-added yogurts showed a notably less sourness score and a higher astringency score than the control. An earthy flavor was higher in 0.45% NPES-supplemented yogurt compared with the control. Based on the results obtained from the current study, the concentration (0.15 to 0.30%, wt/vol) of NPES can be used to formulate NPES-supplemented yogurt without any significant adverse effects on the physicochemical, microbial, and sensory properties.

Influence of different proteolytic strains of Streptococcus thermophilus in co-culture with Lactobacillus delbrueckii subsp. bulgaricus on the metabolite profile of set-yoghurt.

Proto-cooperation between Streptococcus thermophilus and Lactobacillus delbrueckii subsp. bulgaricus is one of the key factors that determine the fermentation process and final quality of yoghurt. In this study, the interaction between different proteolytic strains of S. thermophilus and L. delbrueckii subsp. bulgaricus was investigated in terms of microbial growth, acidification and changes in the biochemical composition of milk during set-yoghurt fermentation. A complementary metabolomics approach was applied for global characterization of volatile and non-volatile polar metabolite profiles of yoghurt associated with proteolytic activity of the individual strains in the starter cultures. The results demonstrated that only non-proteolytic S. thermophilus (Prt-) strain performed proto-cooperation with L. delbrueckii subsp. bulgaricus. The proto-cooperation resulted in significant higher populations of the two species, faster milk acidification, significant abundance of aroma volatiles and non-volatile metabolites desirable for a good organoleptic quality of yoghurt. Headspace SPME-GC/MS and (1)H NMR resulted in the identification of 35 volatiles and 43 non-volatile polar metabolites, respectively. Furthermore, multivariate statistical analysis allows discriminating set-yoghurts fermented by different types of starter cultures according to their metabolite profiles. Our finding underlines that selection of suitable strain combinations in yoghurt starters is important for achieving the best technological performance regarding the quality of product.

Effect of dairy powders fortification on yogurt textural and sensorial properties: a review.

Yogurts are important dairy products that have known a rapid market growth over the past few decades. Industrial yogurt manufacture involves different processing steps. Among them, protein fortification of the milk base is elemental. It greatly enhances yogurt nutritional and functional properties and prevents syneresis, an undesirable yogurt textural defect. Protein enrichment can be achieved by either concentration process (evaporation under vacuum and membrane processing: reverse osmosis and/or ultrafiltration) or by addition of dairy ingredients. Traditionally, skim milk powder (SMP) is used to enrich the milk base before fermentation. However, increased quality and availability of other dairy ingredients such as milk protein isolates (MPI), milk protein concentrates (MPC) whey protein isolates (WPI) and concentrates (WPC), micellar casein (MC) and caseinates have promoted their use as alternatives to SMP. Substituting different dry ingredients for skim milk powder in yogurt making affects the yogurt mix protein composition and subsequent textural and sensorial properties. This review focuses on various type of milk protein used for fortification purposes and their influence on these properties.