Fortification of set yogurt with passion fruit juice: Effects on fermentation kinetics, physicochemical properties, and functionality

Techno-functional properties and enhanced consumer acceptance of whipped fermented milk with Ficus carica L. By-products

The development of new fermented milks formulations enriched with fruit by-products may widen the existing market offer of products matching consumer demands on novel, and "no artificial added sugars" products. Unmarketable fig fruit, food by-product, could be considered as a potential ingredient to develop a new dairy product. The aim of this study was to study the consumer acceptance of fermented milk enriched with different percentage of pasteurized fig purée (by-products) and their technological properties. It was found that the quantity of fig puree added influenced fermented milks texture and spontaneous syneresis. Formulations containing 40% fig puree showed the highest values of firmness, consistency, cohesiveness, and viscosity index with improvements seen from 20% fig puree addition. Furthermore, the inclusion of fig puree in fermented milks reduced the levels of lactic acid bacteria comparing with control samples, but the microbial load was higher than 106 UFC g-1 LAB (estimated counts in MRS) and 9 UFC g-1 LAC (estimated counts in M17). Polyphenolic content increased with fig puree percentage, enhancing antioxidant activity. Volatile compound analysis identified hexanoic acid, acetoin, and butanoic acid as predominant in enriched fermented milks. It is also worth highlighting that sensory evaluation revealed better ratings for texture and sweetness acceptance in formulations containing 30% and 40% of fig puree, correlating with instrumental data. Overall, the quality parameters were maintained and even improved, leading to high consumer acceptability ratings.

Fortification of yogurt with mulberry leaf extract: Effects on physicochemical, antioxidant, microbiological and sensory properties during 21-days of storage

Mulberry leaves are medicinal and edible, with many physiological functions. To improve the potential function of yogurt, the effects of mulberry leaf extract (MLE) incorporation on the fermentation kinetics, physicochemical, antioxidant properties, and sensory parameters of yogurt were evaluated. The results showed that 0.1-0.3 % MLE improved the acidification rate and shortened the fermentation process. The addition of MLE significantly increased the values of total titratable acids, water holding capacity (WHC), total phenolic content and antioxidant capacities of the yogurt (p＜0.05). Specifically, the WHC values of 0.1 % MLE added yogurt were 1.33-1.41 times that of the control over 21 days of storage. In addition, MLE changed the texture and sensory quality of yogurt, resulting in light green, more stable products. Compared to the control, the yogurt with an appropriate concentration of MLE (0.1 % and 0.2 %) showed stable microbiological properties, and the survival of lactic acid bacteria in the yogurt was able to maintain a stable probiotic count of 108 CFU/g over 21 days of shelf life. The yogurt containing 0.1 % MLE achieved a good balance between the physicochemical and sensory qualities of the yogurt, and the use of MLE as an ingredient in yogurt production was a step towards the development of healthier dairy products.

Instant stevia powder as a novel potential additive for enhancing nutritional value and quality characteristics of yogurt

In the current study, yogurts containing instant stevia powder (ISP) at varying proportions (0.1, 0.2, 0.3, and 0.4 g/100 mL) were perused in terms of physicochemical attributes, textural behavior, antioxidant activity, and sensory acceptability during 14 day storage at 4 °C. For this, bioactive components extracted by using microwave-assisted system were spray dried in optimum conditions (11 mL/min flow rate and 167 °C inlet air temperature) and then incorporated into yogurts. The minimal syneresis value (17.09 g/100 g) at the day of 14 was detected in ISP (0.4 g/100 mL)-supplemented yogurts while this value was reached to 19.45 g/100 g in control counterpart without stevia powder. Enriching yogurts with powders was a plausible way for boosting their mechanical properties. The antioxidative parameters namely total phenolic content (TPC), DPPH, ABTS, FRAP, and CUPRAC values were tendency to increase with ISP increment in yogurts. Low scores in sensory evaluation were detected in yogurts loaded with ISP above a certain amount (more than 0.2 g/100 mL). Sum up, the findings proved that the hypotheses (fabricating innovative dairy product rich in bioactive substances and maintaining quality parameters of yogurts during storage) predicted for this study were successfully achieved.

Supplementary Information

The online version contains supplementary material available at 10.1007/s13197-023-05892-z.

Effect of Whole Egg Liquid on Physicochemical, Quality, Fermentation and Sensory Characteristics of Yogurt

With the purpose of developing an alternative set yogurt with high consumer acceptability, liquid whole egg (LWE), at levels that varied from 0 to 30%, was incorporated into set yogurt, and the effects on the physicochemical, quality, fermentation, and sensory characteristics of yogurt were evaluated. The fat content was lower in egg yogurt than in control yogurt. All color variables were significantly affected by LWE amount. The amount of bacteria in the egg yogurt was greater than in the control yogurt. Sensory analysis data suggested that color, odor, and texture consistently impacted the overall acceptability of the egg yogurt. The addition of 5% whole egg, which resulted in an increase of 6.28-fold in hardness, increase of 6.1-fold in viscosity, decrease in pH values, and a 5.6% decline in water-holding capacity (WHC). The aroma and flavor of the set yogurt was improved as well. LWE addition significantly increased the protein content and dynamic rheology. More importantly, the addition of LWE increased the protein content of the set yogurt. This investigation demonstrated the feasibility of fabricating LWE-enriched set yogurt and its superior quality compared with the corresponding normal product. It also emphasized the reconstruction of LWE with enhanced properties.

Small molecule linoleic acid inhibiting whey syneresis via interact with milk proteins in the fermentation of set yogurt fortified with c9,t11-conjugated linoleic acid

The study aimed to investigate the impact of fermentation conditions on c9,t11-conjugated linoleic acid (CLA) synthesis by Lactobacillus casei, as well as its effects on whey syneresis, water holding capacity (WHC), and texture characteristics of set yogurt. The amount of whey syneresis decreased about 30% with the adding of 0.1% linoleic acid (LA). The interaction between LA and casein (CS), β-lactoglobulin (β-Lg) and bovine serum albumin (BSA) was observed by UV-Vis absorption spectroscopy, 3D fluorescence spectroscopy and CD spectroscopy. It found that LA changed the microenvironment and polarity around amino acids, as well as the conformation of the three milk proteins. Scanning electron microscope (SEM) analysis revealed that the addition of LA resulted in a more uniform and compact microstructure of the set yogurt. It indicates that LA can promote the crosslink of milk proteins, which may be the reason for the reduction of whey syneresis in set yogurt.

Phytochemistry, nutritional composition, health benefits and future prospects of Passiflora: A review

Passiflora, also known as "passion fruit", is widely grown in tropical and subtropical regions. It is not only eaten raw but is also widely used in processed foods. Various extracts, juices and isolated compounds show a wide range of health effects and biological activities, such as antioxidant, anti-inflammatory, sedative, and neuroprotective effects. In this review, we not only review the phytochemical properties of Passiflora but also highlight the potential of Passiflora for food applications and the use of all parts as a source of ingredients for medicines and cosmetics that promote health and well-being. This will provide theoretical support for the integrated use of such natural products.

Functional stirred yogurt manufactured using co-microencapsulated or free forms of grape pomace and flaxseed oil as bioactive ingredients: Physicochemical, antioxidant, rheological, microstructural, and sensory properties

Functional stirred yogurt samples were manufactured with combinations of grape pomace (GP) and flaxseed oil (FO) in microencapsulated or free forms (2% w/w) and quality characteristics of yogurts were investigated during 21 days of storage. The incorporation of GP and FO in microencapsulated or free forms caused a significant decrease in pH, syneresis, and a significant increase in acidity, water holding capacity, and viscosity of stirred yogurt (p < .05). While stirred yogurt containing GP and FO in free form had the highest loss modulus (G″), all yogurt samples represented solid-like behavior. Stirred yogurts containing the microencapsulated form of GP and FO showed the highest amount of phenolics and antioxidant activity compared with the two other yogurt samples (p < .05). More compact structure and higher gel strength were observed in stirred yogurts formulated with the microencapsulated or free form of GP and FO, compared to the control yogurt sample. The overall sensory acceptability of stirred yogurt manufactured using the encapsulated form of GP and FO was not significantly different from the control yogurt sample (p > .05). In conclusion of this competitive study, GP and FO as bioactive compounds could be used in the microencapsulated form in order to develop functional stirred yogurt with specific quality characteristics.

Properties of Yoghurt Fortified in Lactoferrin with Effect of Storage Time

The stability of fortified yoghurts during refrigerated storage is important for industry and the consumer. The aim of the study was to evaluate the nutritional value, microbiological quality, organoleptic properties, and structure of natural yoghurts made with the addition of lactoferrin during refrigerated storage. In this study, we produced natural yoghurts fortified in lactoferrin, using YC-X11 yoghurt starter culture based on Lactobacillus delbrueckii subsp. bulgaricus and Streptococcus thermophilus. Physicochemical (acidity, nutritional value and structure) as well as microbiological and organoleptic changes occurring during 28-days refrigerated storage were determined. Storage research made it possible to determine the direction of changes taking place in the products. The analysed parameters did not differ statistically significantly between the control yoghurts and those with the addition of lactoferrin. Textural and rheological studies also shown that the addition of lactoferrin did not significantly change the structure of the yoghurt. The yoghurts were characterized by high sanitary and hygienic quality during the whole refrigerated storage. Lactoferrin has a positive effect on the durability of the product.

A Review on Processing Opportunities for the Development of Camel Dairy Products

Camel milk has a significant and pivotal role in the diet of people residing in semi-arid and arid regions. Ever since ancient times, marketing of camel milk has remained insignificant due to nonexistence of processing amenities in the camel nurturing areas, hence the utilization of unprocessed camel milk has continuously remained limited at family level by the nomads. Due to the superior medicinal values and health promoting effects, incredible growth in the demand of camel milk and dairy products have been noticed all over the world during last two decades. Such emergence has led dairy industry to provide diversified camel dairy products to the consumers with superior nutritional and functional qualities. In contrast to bovine, very few food products derived from camel milk are available in the present market. With the advancements in food processing interventions, a wide range of dairy and non-dairy products could be obtained from camel milk, including milk powder, cheese, yogurt, ice cream, and even chocolate. In some regions, camel milk is used for traditional dishes such as fermented milk, camel milk tea, or as a base for soups and stews. Current review highlights the processing opportunities regarding the transformation of camel milk into various dairy products via decreasing the inherent functionality that could be achieved by optimization of processing conditions and alteration of chemical composition by using fortification method. Additionally, future research directions could be devised to improve the product quality.

Supplementation of Labneh with Passion Fruit Peel Enhanced Survival of E. coli Nissle 1917 during Simulated Gastrointestinal Digestion and Adhesion to Caco-2 Cells

Passion fruit peel powder (PFPP) was used to supplement the probiotic labneh to increase the activity of Escherichia coli Nissle 1917 (EcN) during production and storage. Labneh was manufactured with PFPP (0.5% and 1%) and analyzed at 0, 7, and 15 days of cold storage for postacidification and sensory properties and viability of EcN, survival of EcN to simulated gastrointestinal tract stress, and adhesion potential of EcN to Caco-2 cells. Acidification kinetics during fermentation showed that supplementation with PFPP reduced the time needed to decrease pH and reach the maximum acidification rate. PFPP addition contributed to postacidification of labneh during storage. PFPP had a beneficial effect (p < 0.05) on counts of EcN in labneh during different storage periods. Consumer preference expectations for labneh enriched with PFPP (0.5% and 1%) were higher than those for the control. PFPP provided a significant protective action for EcN during simulated gastrointestinal transit and had a positive effect on EcN adhesion to Caco-2 cells in vitro, although this decreased during storage with labneh. Labneh supplementation with PFPP can be recommended because of the positive effect on EcN viability and the high nutritional value, which may increase the appeal of the product to consumers.

Evaluation of passion fruit mesocarp flour on the paste, dough, and quality characteristics of dried noodles

Reasonable intake of high-fiber staple food is already one of the most effective measures in fiber deficiency disease prevention and control. Passion fruit mesocarp flour (PFMF), the primary byproduct during passion fruit processing, was utilized to manufacture high-fiber dried noodles. The presence of PFMF boosted wheat flour gelatinization and retrogradation. The competition for water between PFMF and wheat flour inhibited the formation of the gluten network, which harmed the cooking properties and decreased consumer acceptance of the resulting dried noodles. Nevertheless, PFMF fortification could considerably increase the dietary fiber content of noodles. Especially for noodles with 9% PFMF, the total dietary fiber content was greater than 6%, and they thus could be regarded as a high-dietary-fiber food. Generally, the current work demonstrates the feasibility of fabricating PFMF-enriched dried noodles and their nutritional superiority compared to the corresponding normal product.

Fermented oat milk as a base for lactose-free sauce

Introduction. We studied the use of fermented oat milk to produce sauce and evaluated its properties. The research was motivated by the current demand for so called “plant milk” commonly perceived as an alternative to cow’s milk. Study objects and methods. The experimental samples were produced from oats-based drinks (1.5 and 3.2% fat) fermented with starter cultures of lactic acid microorganisms following the guidelines for yoghurt production. Apple pectin was used as a thickener. Rheological studies were performed using an RM-1 rotational viscometer and a CT-2 texture analyzer according to the standard methods. Sensory evaluation was based on a scoring scale. Physicochemical parameters were determined according to generally accepted methods. Results and discussion. Oat milk was fermented to produce a sauce base. Acid accumulation increased throughout fermentation up to 135–137°T. Apple pectin (3%) was added to stabilize the structure and ensure the desired consistency. Higher concentrations of pectin increased the hardness and adhesive strength of the samples from both 1.5 and 3.2% oat milk. The 1.5% sauce scored highest in the sensory evaluation. Its physicochemical indicators met the standard requirements for related fermented milk products. We found the best consistency indicators at a pectin concentration of 3%. Conclusion. The new fermented sauce based on low fat oat milk (1.5% fat) had high consumer appeal as well as physicochemical, sensory, and rheological characteristics. The sauce can be used by people with lactose intolerance and vegetarians.

Investigation of the effects of pomegranate juice addition on physicochemical, microbiological, and functional properties of set and stirred yogurts

Pomegranate juice (PJ) (at concentrations of 13% and 17%) was added to yogurt and its physicochemical and microbial properties were investigated. PJ improved several features of yogurt, bringing an increase in total phenolic contents by 4.3-6.1 and 5.3-7.3 fold in response to 13% and 17% PJ, respectively. Also, there were increases in the total anthocyanin contents of yogurt by 2650-2870 and 3470-3820 fold in response to the said juice concentrations. These increases were observed in both set and stirred yogurts, whereas IC50 values of the yogurts decreased by 2.2-2.6 and 3.0-3.3 fold, respectively, compared to the control samples. Total acidity, syneresis, and redness value of the yogurts increased, parallel to the increase in the PJ concentration being added. Also, Streptococcus thermophilus count decreased significantly, whereas no significant effect was observed on the population count of Lactobacillus delbrueckii subsp. bulgaricus. Among PJ yogurt samples, the panelists selected the 13% PJ stirred yogurt as the best sample. PJ was observed to contain valuable bioactive compounds with functional and medicinal effects that culminate in health benefits.

Effect of Supercritical Extract from Black Poplar and Basket Willow on the Quality of Natural and Probiotic Drinkable Yogurt

Yogurt is a fermented milk drink produced by Streptococcus thermophilus, Lactobacillus delbrüeckii ssp. bulgaricus, or Lactobacillus rhamnosus, which can be enriched with polyphenolic compounds to enhance its antioxidant properties. Supercritical (scCO2/H2O) extracts obtained from the mixture of bark and wood of black poplar (Populus nigra) and basket willow (Salix viminalis) are the source of bioactive compounds. The aim of the study was to assess the effect of supercritical extracts from the P. nigra and S. viminalis on the fermentation, quality, and bioactive properties of drinkable natural and probiotic yogurts. The incorporation of scCO2/H2O extracts at a dose of 0.01% (w/v) into milk for the production of natural and probiotic yogurts increases their functional properties by enhancing the antioxidant activity without causing negative effects on the physicochemical and organoleptic properties of products. The antioxidant activity of yogurt with scCO2/H2O extract from P. nigra and S. viminalis was higher than control yogurts by 1.3-13.2% and 4.4-37.5%, respectively. The addition of a supercritical S. viminalis extract reduced the time of natural and probiotic yogurt fermentation. Natural and probiotic yogurt with scCO2/H2O extracts added was characterised by a bacterial population size of over 7 log cfu/g, and the microflora was active throughout the cold storage period. FTIR analysis confirmed the presence of scCO2/H2O extracts from P. nigra or S. viminalis in both types of yogurt. A secondary structure analysis confirmed interactions between compounds of scCO2/H2O extract from P. nigra and S. viminalis extract with milk proteins. These interactions affect the compounds' structural and functional properties by changing, e.g., their digestibility and antioxidant properties.