Quality characteristics and antioxidant activities of goat milk yogurt with added jujube pulp

Fortification of goat milk yogurts with date palm (Phoenix dactylifera L.) coproducts: Impact on their quality during cold storage

The aim of this study was to investigate the impact of different concentrations (3% and 6%) of two ingredients (paste and flour) obtained from the valorization of date fruit coproducts on the nutritional (proximate composition and mineral profile), technological (coagulation curve, pH, acidity, sugar and organic acid content and syneresis), physicochemical (color, water activity and texture), microbiological and sensory properties of goat's yogurt during 21 days of refrigerated storage. Both ingredients enhanced the growth and stability of the yogurt starter culture, thereby improving the probiotic potential of date-added yogurts. Physicochemically, the addition of date flour (at both concentrations) induces stronger modifications (texture, color and syneresis) in yogurts than the date paste. During storage, date paste reduced the syneresis and hence maintained yogurts' physical quality. Consumers preferred the yogurts with date paste (3% and 6%) rather than with date flour, because its addition led to a more brownish color and granular texture.

Metabolite profiling of camel milk and the fermentation bacteria agent TR1 fermented two types of sour camel milk using LC-MS in relation to their probiotic potentials

Camel milk is a nutrient-rich diet and fermentation affects its nutritional value and probiotic function. In this study, sour camel milk and oat jujube sour camel milk were prepared using fermentation bacteria agent TR1, and the metabolites of camel milk, sour camel milk and oat jujube sour camel milk were detected using a non-targeted metabolomics approach using liquid chromatography-mass spectrometry (LC-MS).The results showed that the partial least squares discriminant analysis (PLS-DA) with 100 % accuracy and good predictive power detected 343 components in positive ion mode and 220 components in negative ion mode. The differential metabolites were mainly organic acids, amino acids, esters, vitamins and other substances contained in camel milk.It showed that there were significant differences in the metabolites of camel milk, sour camel milk and oat jujube sour camel milk. Based on the pathway enrichment analysis of the three dairy products in the KEGG database, 12 metabolic pathways mainly involved in the positive ion mode and 20 metabolic pathways mainly involved in the negative ion mode were identified. The main biochemical metabolic pathways and signal transduction pathways of the differential metabolites of the three dairy products were obtained. This study provides theoretical support for improving the nutritional quality and probiotic function of camel milk and fermented camel milk products and provides a basis for the development of relevant processing technologies and products for camel milk and fermented camel milk.

Effect of jujube pulp on acid- and rennet-induced coagulation properties of milk

Milk coagulation is an important step in the production of fermented dairy products such as yogurt and cheese. Jujube is gaining popularity and acceptance as a food ingredient. In China, jujube yogurt is popular among consumers. However, there is limited information on the effect of jujube on acid- and rennet-induced coagulation properties of milk. The objective of this study was to evaluate the effects of jujube pulp at different concentrations on acid- and rennet-induced coagulation kinetics of milk and the microstructure of acid- and rennet-induced gels. During acid-induced coagulation, with increasing jujube pulp concentration, the initial pH value decreased; however, the final pH value increased. The initial elasticity index (EI) value increased, and the time point at which the mean square displacement curves lost the linear trend advanced. The sample with 10% jujube pulp had the densest structure and highest EI value. During rennet-induced coagulation, with increasing jujube pulp concentration, the production rate and amount of caseinomacropeptide decreased, and the final EI value increased. Protein aggregates in rennet-induced gels became rough, and the sample with 20% jujube pulp had the highest EI value. This study provides a new perspective and understanding of the application of jujube in fermented dairy products.

Effect of Blueberry Pomace Addition on Quality Attributes of Buttermilk-Based Fermented Drinks during Cold Storage

The fruit and beverage industry faces challenges related to waste management and environmental pollution due to rapid industrial expansion. Fruit industry waste, such as blueberry pomace, holds the promise of enhancing gut health and providing valuable antioxidants. Concurrently, buttermilk, a prominent dairy product, offers nutritional and technological benefits but remains underutilized. This study aimed to evaluate the incorporation of blueberry pomace (0%, 2%, 4%, 6%, 8%, and 10%) into buttermilk at varying levels and assess its impact on the physicochemical, antioxidant, microbiological, and sensory characteristics of the buttermilk. Buttermilk samples were supplemented with different concentrations of blueberry pomace and subjected to analysis over a two-week storage period (4 ± 1 °C). The addition of blueberry pomace led to alterations in the pH, dry matter, water holding capacity, color parameters, total phenolic content, and antioxidant activity. Microbiological analysis revealed the absence of Enterobacteriaceae, yeast, or molds. Sensory evaluation indicated significant differences among samples, with the highest scores observed for the buttermilk supplemented with 2% and 4% blueberry pomace. Incorporating blueberry pomace improved the overall acceptability and sensory properties. This research highlights the potential of fruit industry by-products to enhance the functionality and health benefits of dairy products, which is a promising way to effectively utilize waste.

Functional properties and flavor characteristics of milk from cows supplemented with jujube powder

Jujube has various functional properties and is a promising source of bioactive compounds and flavors. This study investigated the functional properties and flavor characteristics of milk from cows supplemented with jujube powder (JP). Here, milk volatile profiles and taste properties were analyzed by using an electronic nose and headspace solid-phase microextraction GC-MS. Compared with the control group, the total antioxidant capacity, 2,2'-azino-bis-3-ethylbenzothiazoline-6-sulphonic free-radical-scavenging activity, lactoferrin, and IgG levels increased significantly in the JP group. Volatile flavor analysis indicated that ketone levels increased, acid abundance decreased, and toluene and dimethyl sulfone significantly increased in the JP group. Taste-profile analyses demonstrated that jujube supplementation altered the taste of the milk. In summary, dietary JP supplementation affects the volatile flavor composition and aroma of milk, as well as the bioactive components and antioxidant properties. These findings enhance our understanding of milk production using direct dietary supplementation to produce sustainable dairy products.

Production of Acid and Rennet-Coagulated Cheese Enriched by Olive (Olea europaea L.) Leaf Extract-Determining the Optimal Point of Supplementation and Its Effects on Curd Characteristics

This study investigated the potential of olive leaf extract (OLE), as a functional ingredient, to improve cheese properties, because it is rich in phenols. Milk and dairy products are poor in phenolic compounds. The main objective was to determine the most effective coagulation method and timing of OLE supplementation to maximize retention in the cheese matrix. Experimental cheeses were produced using the rennet and acid coagulation methods, with OLE added either directly to the cheese milk or to the curd phase. Three OLE effective concentrations corresponding to 25%, 50%, and 75% inhibition of DPPH reagent (EFC25, EFC50, and EFC75, respectively) were added, i.e., 11.5 mg GAE L-1, 16.6 mg GAE L-1, and 26.3 mg GAE L-1, respectively. The results showed that OLE significantly increased the concentration of total phenols, total flavonoids, and antioxidant activity in all cheese samples and in the residual whey, especially at higher effective concentrations (EFC 50 and EFC 75). Rennet-coagulated cheese to which OLE was added prior to coagulation (EM 25, EM 50, EM 75) exhibited higher hardness, gumminess, and chewiness but lower elasticity, suggesting alterations in the paracasein matrix. OLE did not adversely affect acidity, water activity, or cheese yield. However, higher EFC resulted in significant colour changes (∆E* > 3.0). In conclusion, the enrichment of cheesemaking milk with OLE and the application of the rennet coagulation method are the most suitable to optimise the production of OLE-enriched cheese. This research shows the potential to improve the nutritional value of cheese while maintaining its desired characteristics.

Synergistic effects of lactobacillus strains and Acetobacter pasteurianus on jujube puree's product functionality and quality

Commercial lactic acid bacteria strains and indigenous Chinese acetic acid bacterium were co-cultivated bi- and tri-culturally in Junzao jujube puree for the first time to investigate their effects on physicochemical properties and quality attributes. Lactic-acetic acid bacteria co-fermentation was performed at 37 °C for 48 h during the anaerobic fermentation phase and at 30 °C for 144 h during aerobic fermentation. FTIR results showed that predominant wave numbers at 1716-1724 cm-1 and 2922-3307 cm-1 exhibited discernible alterations in the lactic-acetic acid co-fermented jujube purees compared to the control sample. Pearson correlation analysis showed that the flavonoid and flavonol contents were responsible for the enhanced 2,2'-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) and 2,2-diphenyl-1-picrylhydrazyl scavenging activities of the fermented jujube purees. Consequently, fermented jujube puree from tricultures of Lactobacillus casei, Lactobacillus plantarum, and Acetobacter pasteurianus gave the best results, with the highest phenolics, flavonoid, and flavonol contents and the most improved antioxidative properties and color. Overall, lactic-acetic acid bacteria co-culture holds significant promise in valorizing Junzao jujube purees for functional ingredient development, paving the way for further research into similar interactions with different food matrices or microbial strains.

Investigation of some quality properties of yogurt made from cow and sheep milk fortified with folic acid (B9 ), biotin (B7 ), and vitamin D3

BACKGROUND

The aim of this study was to investigate the effects on some physicochemical properties and starter cultures of yogurts enriched with vitamins at different concentrations during storage. For this purpose, yogurt was produced by adding the vitamins folic acid (B9 ), biotin (B7 ), and vitamin D3 in different concentrations to sheep and cow milk and stored at 4 °C. Physicochemical analyses and microbiological analyses were performed for each group of yogurt on days 0, 7, 14, and 21.

RESULTS

There was no significant difference (P > 0.05) between the groups in pH and titration acidity (%) during storage. It was determined that in the yogurts produced from sheep milk, the groups enriched with vitamins had a higher number of L. bulgaricus than the control group on the 7th day of storage. Moreover, the groups containing vitamin D3 exhibited a higher Lactobacillus bulgaricus count on the 21st day of storage. The highest L. bulgaricus counts on the 7th day in yogurts produced from cow's milk were observed in groups containing 0.5 mL of vitamin B9 and B7 . No mold or yeast growth was observed during storage in any of the yogurt groups made from cow and sheep milk.

CONCLUSION

In conclusion, it was determined that the enrichment of yogurt with vitamins B7 , B9 , and D3 did not adversely affect the quality of the yogurt; rather, it improved. We recommend that yogurt enriched with micronutrients be studied economically, and mass production should be initiated by yogurt companies as soon as possible. © 2023 Society of Chemical Industry.

Effects of Jujube Powder on Growth Performance, Blood Biochemical Indices, and Intestinal Microbiota of Broiler

In total, 576 Cobb broilers were randomized into 6 treatment groups, with 8 replicates in each treatment group and 12 broilers in each replicate. Each treatment group was fed six different experimental diets containing 0%, 2%, 4%, 6%, 8%, and 10% jujube powder. The group receiving 0% jujube powder was considered the blank control group. The experimental period was 42 days and was divided into two periods: starter (0-21 days) and finisher (22-42 days). Compared with the control group, the addition of 8% jujube powder significantly improved the ADG of broilers (p < 0.05), and 8% and 10% jujube powder significantly improved the total tract apparent digestibility of organic matter in broilers (p < 0.05). Adding 10% jujube powder significantly improved the apparent metabolic energy of broilers (p < 0.05). Compared with the control group, 4-10% jujube powder significantly increased IgA, IgG, IgM, and sCD4 levels (p < 0.05) and T-AOC and SOD contents, and it reduced the MDA content in the serum of broilers (p < 0.05). In addition, the relative abundance of Firmicutes, Bacteroidetes, Lactobacillus, and Romboutsia significantly increased in the broiler ileum, whereas that of Proteobacteria and Enterobacter decreased significantly (p < 0.05) when 8% jujube powder was added to the diet. The relative abundance of Proteobacteria, Bacteroides, and Faecalibacterium in the cecum increased significantly (p < 0.05), whereas that of Bacteroidetes decreased significantly (p < 0.05).

Characterization and application in yogurt of genipin-crosslinked chitosan microcapsules encapsulating with Lactiplantibacillus plantarum DMDL 9010

Microcapsules could improve the protection of probiotics in the lyophilization and gastrointestinal digestion process. The purpose of this study was to prepare Lactiplantibacillus plantarum DMDL 9010 (LP9010) microcapsules by cross-linking chitosan with genipin and to determine the encapsulation efficiency, morphological characterization, storage stability and the application of the microcapsules in fermentation. The results showed that the LP9010 microcapsules embedded in 1.00 wt% genipin cross-linked chitosan were in a uniform spherical shape with a smooth surface and satisfying agglomeration. The LP9010 microcapsules demonstrated the reasonable thermal stability and persistence of biological activity in the range of -20 °C to 25 °C. Additionally, yogurt obtained from the ST + LB + ELP9010 strain formulation with the addition of microencapsulated LP9010 had smaller particles, better taste, and better stability compared with the yogurt obtained from other strain formulations. As detected by GC-MS, the yogurt formulated with ST + LB + ELP9010 as a strain retained more flavor substances and the content of flavor substances was greater than that of the yogurt obtained from other strain formulations. Therefore, genipin cross-link chitosan could be a suitable microencapsulated material for producing yogurt fermentation strains.

Combination of enzymatically hydrolyzed potato powder with skimmed milk powder on the quality improvements of yogurt during refrigeration storage

This study aimed to prepare a stirred type of fat-free yogurt from enzymatically hydrolyzed potato powder (EHPP) and skimmed milk powder (SMP) without changing its quality and consumer acceptance. The yogurt formulations prepared contained different amount of EHPP 0, 10, 25 and 50% and were stored for 28 days at 4 °C and observed that with increasing substitution ratio, acid production was increased while the viability of lactic acid bacteria was decreased after 28 days of storage at 4 °C. The antioxidant activities (2-Diphenyl-1-picryl-hydrazyl (DPPH) free radical scavenging activity and ferric reducing antioxidant power (FRAP) of the yogurt were increased with increasing EHPP over the storage period. The yogurt formulations having 25 to 50% EHPP has the highest DPPH free radical scavenging activity and FRAP values. Water holding capacity (WHC) was decreased over the storage period with 25% EHPP. The hardness, adhesiveness and gumminess were decreased while no significant change was found in springiness with EHPP addition over the storage period. The rheological analysis showed an elastic behavior of yogurt gels with EHPP supplementation. The sensory results of yogurt containing 25% EHPP have the highest values of taste and acceptance. Yogurt in combination with EHPP and SMP has the higher levels of WHC than non-supplemented yogurt and better stability was recorded during storage.

Supplementary Information

The online version contains supplementary material available at 10.1007/s13197-023-05737-9.

Stability and flavor of set yogurt fortified with Tremella fuciformis polysaccharide during cold storage

Tremella fuciformis is an edible and medicinal fungus containing excellent nutritional value. T. fuciformis polysaccharide (TFP) is the important bioactive ingredients of T. fuciformis, which has gained great attention. The aim of this study was to investigate the effect of TFP on the stability and flavor of set yogurt. Our results revealed that the addition of 0.1% TFP had a positive effect on improving the stability of set yogurt including the water holding capacity, texture, rheological properties and microstructure at the cold storage period of 1, 7, 14 and 21 days. It is remarkable that the hardness, gumminess and chewiness of the set yogurt were significantly improved by the addition of TFP during the cold storage. Moreover, the set yogurt containing TFP was able to maintain better stability in the three intervals thixotropy test. In particular, the addition of 0.1% TFP had no adverse effects on the flavor of set yogurt, including sourness, sweetness, umami, bitterness, richness and saltiness. These data suggested that TFP can be used as a natural potential stabilizer for the set yogurt.

Development of a novel functional yogurt rich in lycopene by Bacillus subtilis

Functional lycopene-rich yogurt displays attractive nutritious and health-promoting benefits among existing functional dairy products, owing to supplement with lycopene which could enhance immunity, prevent cancer, and cardiovascular diseases. Due to poor stability and fat-solubility of lycopene, its incorporation into yogurt is challengeable. In this study, carotenoid genes for lycopene synthesis were co-introduced into probiotic Bacillus subtilis for efficient lycopene production. Further engineered B. subtilis was applied as adjunct starter culture for achieving lycopene-rich yogurt. Developed yogurt exhibited desirable physiochemical characteristics compared with plain yogurt. Moreover, lycopene-rich yogurt was endowed with significantly high antioxidant capacity. More importantly, this functionalized yogurt had attractive sensorial attributes for quality-assured food to facilitate consumer acceptance. As the first report of fortifying yogurt of lycopene using B. subtilis with improved functional properties, this study offers a new and facile clue to enrich bioactive lycopene and probiotic B. subtilis in yogurt for healthy and nutritional food development.

Composition Analysis and Nutritional Value Evaluation of Amino Acids in the Fruit of 161 Jujube Cultivars

Amino acids are an essential group of compounds involved in protein synthesis and various metabolic and immune reactions in the human body. Chinese jujubes (Ziziphus jujuba Mill.) are an important fruit and medicinal plant which are native to China and have been introduced into around 50 countries. However, systematic research on the composition and content diversity of amino acids in the jujube is still lacking. In this experiment, the amino acid composition and the contents of the dominant amino acids in the fruit of 161 cultivars of jujube were determined by HPLC. Of the twenty-one kinds of amino acids detected, a total of fourteen kinds of amino acids were detected, of which eight kinds of amino acids were relatively high, including five essential amino acids (threonine, valine, isoleucine, leucine, and phenylalanine) and three nonessential amino acids (glycine, alanine, and proline). However, the contents of the remaining six amino acids were relatively low (aspartic acid, glutamic acid, histidine, serine, arginine, and tryptophan). Therefore, the eight primary amino acids were used as the index to evaluate the amino acids of 161 jujube varieties. Proline accounts for 56.8% of the total amino acid content among the eight amino acids. The total content of the eight primary amino acids in most jujube varieties was 1-1.5 g/100 g, and the highest content of 'Zaoqiangmalianzao' was 2.356 g/100 g. The average content of proline was 6.01-14.84 times that of the other seven amino acids. According to the WHO/FAO revised model spectrum of ideal essential amino acids for humans, 19 cultivars met the E/T (essential amino acids/total amino acids) standard, and their values ranged from 35% to 45%; 12 cultivars meet E/NE (non-essential amino acids) ≥ 60%. All cultivars reached the requirement of BC (branched-chain amino acids)/E ≥ 40% with 15 cultivars over 68%. One hundred and fifty-seven cultivars reach the standard of BC/A (aromatic amino acids) ≈ 3.0~3.5. The amino acid ratio coefficient analysis showed that phenylalanine was the first limiting amino acid of all the jujube cultivars. The SRC (the score of amino acid ratio coefficient) values of 134 cultivars were between 50% and 70%, with 12 cultivars over 70%, indicating that jujube fruits are of high nutritional value in terms of amino acids. Based on the principal component analysis and comprehensive ranking of amino acid nutritional value, the top five cultivars were screened from the 161 ones tested, i.e., 'Tengzhouchanghongzao', 'Xinzhengxiaoyuanzao', 'Hanguowudeng', 'Xuputiansuanzao', and 'Lichengxiaozao'. This study established, firstly, a complete basic data analysis of amino acid content in jujube fruit which could be used to select germplasm resources suitable for developing functional amino acid food, and provide theoretical support for the high value utilization of amino acids in jujubes.

Dietary Dried Jujube Fruit Powder (DJFP) Supplementation Improves Growth Performance, Antioxidant Stability, and Meat Composition in Broilers

Nowadays, broiler production is faced with great challenges due to intensive culture modes, and chickens are more susceptible to oxidative stress. Consequently, synthetic antioxidants have been used to reduce this process, but their use has shown potential health risks. Thus, the use of natural ingredients has been suggested as a strategy to prevent oxidative stress. This study investigated how dietary dried jujube fruit powder (DJFP) supplementation influences the growth performance, antioxidant stability, meat composition, and nutritional quality of Cobb broilers. A total of 360 unsexed broilers (1-day-old) were randomly assigned to treatments that varied in DJFP levels: a basal diet without DJFP (control) and diets supplemented with 50 g/kg DJFP (P1), 100 g/kg DJFP (P2), and 150 g/kg DJFP (P3), with 9 replicates per treatment (90 broilers/treatment or 10 broilers/replicate). The results demonstrated improvement in the growth performance of broilers in terms of body weight (BW), body weight gain (WG), average daily body weight gain (ADG), average daily feed intake (ADFI), and feed conversion ratio (FCR) following dietary DJFP supplementation. In addition, the antioxidant stabilities in the DJFP-treated broilers were improved and inhibited the production of lipid oxidation products compared with the control, with those in the P2 group showing the most marked effect. Moreover, dietary DJFP supplementation significantly increased (p < 0.05) the activity of antioxidant enzymes in broilers. Furthermore, the breast meat of the broilers displayed an increased protein content with a simultaneous reduction in the fat content after DJFP treatment (p < 0.05). Essential amino acid levels were higher in the DJFP-supplemented groups (p < 0.05). The sum of saturated fatty acids was lower, and that of monounsaturated fatty acids (MUFAs) and the polyunsaturated fatty acid/saturated fatty acid ratio (PUFA/SFA) were higher in the DJFP-supplemented groups (p < 0.05). Together, these results indicate that up to 100 g/kg of dietary DJFP supplementation can enhance the growth performance and antioxidant capacity, meat composition, and amino acid and fatty acid composition in broiler breast meat. In conclusion, dietary DJFP supplementation is a healthy alternative to the use of synthetic antioxidants in broiler production, especially in regions rich in jujube resources.

Encapsulated fucoxanthin improves the structure and functional properties of fermented yogurt during cold storage

Fucoxanthin (FX) extracted from Undaria pinnatifida by an ultrasonic-assisted extraction (UAE) procedure was successfully added to the fermented yogurt through a stably nanoencapsulation. The physicochemical characteristics, texture analysis, rheological testing, sensory evaluation, simulated digestion analysis, and 16SrDNA sequencing analysis were used to evaluate the effect of encapsulated-FX on the function, structure and stability of the fermented yogurt during 7 days cold storage. Encapsulated-FX with a highly water dispersion, changed the microstructure of yogurt, making it more uniform and denser, enhanced the antioxidant activity, increased the stability of milk protein in simulated gastric environment in vitro and promoted the absorption of protein small molecule fragments in the intestine, and inhibited the growth of harmful bacteria during cold storage. This study provided a simple strategy for the production of FX-fortified yogurt by using an effective nanoencapsulation technology, and promoted the extraction and application of active ingredients of edible brown algae.

Effects of Sulla Flexuosa Hay as Alternative Feed Resource on Goat's Milk Production and Quality

Sulla flexuosa (Hedysarum flexuosum L.) is an endemic legume growing in some Mediterranean areas in rainfed and cold mountainous conditions. It could be used in goat diets as an alternative protein source instead of alfalfa to supplement forest rangeland. This study aimed to test the effects of incorporating Sulla flexuosa (SF) hay in the diet of Beni Arouss goats on their milk production and quality. The hay was introduced at two levels, i.e., 35 or 70% (SF70), on a DM basis; it partially or totally replaced the alfalfa hay of the control diet. Sulla flexuosa incorporation did not affect milk production or physicochemical composition. However, milk FA content varied in proportion to the percentage of SF incorporation. The SF70 diet was associated with increased milk levels in C18:1n-9, C18:2n-6, C18:3n-3, and C22:6n-3 and total monounsaturated, polyunsaturated, and n-3 fatty acids. As a consequence, atherogenic and thrombogenic indices were improved. Additionally, better antioxidant capacity was observed in SF70.

Bioactive Compounds Extracted from Saudi Dates Using Green Methods and Utilization of These Extracts in Functional Yogurt

The bioactive compounds of four Saudi date flesh extracts (Ambara (AF), Majdool (MF), Sagai (SF), and Sukkari (SKF)) prepared using different extraction methods-namely, supercritical fluid extraction (SFE), subcritical CO₂ extraction (SCE), and Soxhlet extraction (SXE)-were evaluated. A total of 19 bioactive compounds were detected in extracts prepared using SFE and SCE methods, whereas less than 12 compounds were detected in extracts obtained using the SXE method. Both the date variety and extraction method affected the phenolic profile of date flesh extract (p ≤ 0.05). The apparent viscosity, surface color, and bioactive properties of yogurt were affected by both date flesh extracts and storage duration in varied magnitudes (p ≤ 0.05). The incorporation of date flesh extracts into yogurt formulations increased the total phenolic content (TPC), DPPH antiradical activity, viscosity, and redness (a*) and decreased the lightness (L*) and yellowness (b*) of the developed product (p ≤ 0.05). The elongation of storage time progressively (p ≤ 0.05) reduced the pH, TPC, DPPH antiradical activity, bacterial counts, and L* and b* values and increased the acidity, syneresis, viscosity, and a* values with few exceptions. Date flesh extracts can improve the health quality of yogurt without major influence on the sensory attributes while stored at 4 °C.

Biologically Active Supplements Affecting Producer Microorganisms in Food Biotechnology: A Review

Microorganisms, fermentation processes, and the resultant metabolic products are a key driving force in biotechnology and, in particular, in food biotechnology. The quantity and/or quality of final manufactured food products are directly related to the efficiency of the metabolic processes of producer microorganisms. Food BioTech companies are naturally interested in increasing the productivity of their biotechnological production lines. This could be achieved via either indirect or direct influence on the fundamental mechanisms governing biological processes occurring in microbial cells. This review considers an approach to improve the efficiency of producer microorganisms through the use of several types of substances or complexes affecting the metabolic processes of microbial producers that are of interest for food biotechnology, particularly fermented milk products. A classification of these supplements will be given, depending on their chemical nature (poly- and oligosaccharides; poly- and oligopeptides, individual amino acids; miscellaneous substances, including vitamins and other organic compounds, minerals, and multicomponent supplements), and the approved results of their application will be comprehensively surveyed.

Lactitol and β-cyclodextrin alleviate the intensity of goaty flavor

BACKGROUND

Goat milk has balanced nutritional composition, is conducive to digestion and absorption, and does not easily lead to allergic reactions. However, the special goaty flavor in milk has seriously affected consumer acceptance. It is imperative to alleviate the goaty flavor in a safe and efficient way.

RESULTS

This study indicated that the supplementation of 6 g kg^-1 β-cyclodextrin or 8 g kg^-1 lactitol in goat milk significantly alleviated goaty flavor and improved sensory characteristics. Furthermore, the supplementation of β-cyclodextrin and lactitol had a synergistic effect in reducing the content of free fatty acids that cause goaty flavor. The content of caproic acid (C₆ H₁₂ O₂ ), octanoic acid (C₈ H₆ O₂ ), and decanoic acid (C₁₀ H₂₀ O₂ ) decreased by 42.46%, 39.45%, and 46.41%, respectively, after a combined group was supplemented with 6 g kg^-1 β-cyclodextrin and 7 g kg^-1 lactitol, which was significantly lower than in groups given β-cyclodextrin or lactitol individually.

CONCLUSION

This study provides a novel and effective approach to alleviate goaty flavor and promote the competitiveness of goat milk products. © 2022 Society of Chemical Industry.

Storage stability of texture, organoleptic, and biological properties of goat milk yogurt fermented with probiotic bacteria

Introduction

Goat milk is an attractive food due to its high nutritional values, easy digestibility and hypoallergenicity, but has an undesirable "goaty" flavor.

Methods

In this study, goat yogurt was fermented with four probiotics, respectively, including Lactobacillus acidophilus (GYA), Bifidobacterium animalis (GYB), Lactobacillus casei (GYC) and Lactobacillus plantarum (GYP), and tested for texture, organoleptic, and biological properties during a 4-week storage period at the refrigerated temperature.

Results

All goat yogurt with probiotics showed an increase on titratable acidity and a corresponding downward trend on pH value. Viable counts of L. acidophilus and L. casei were above 6 log cfu/mL at the end of the storage, which met the minimum standards for viable probiotic bacteria in yogurt specified by the Food and Agriculture Organization of United Nation (FAO). The texture and organoleptic characteristics of fermented goat milk depended on the strain and the storage period. DPPH free radical scavenging rate and ferric reducing antioxidant power activity gradually increased in all goat yogurts during the storage and yogurt with probiotic bacteria showed higher values than those of GY0.

Discussion

Among all probiotic containing goat yogurts, GYC exhibited the desirable characteristics of hardness, adhesiveness, water holding capacity, antioxidant activity during the whole storage. Furthermore, the addition of L. casei effectively weakened the goaty flavor and enhanced the overall acceptability. Thus, fermented goat milk with L. casei is optional for the development of goat milk product with satisfactory texture properties, pleasant sensory quality and high bioactivity.

Investigation of the physicochemical, antioxidant, rheological, and sensory properties of ricotta cheese enriched with free and nano-encapsulated broccoli sprout extract

This study aimed to produce the functional ricotta cheese using broccoli sprouts extract (BSE) and to evaluate its physicochemical, antioxidant, rheological, and sensory properties. The BSE nano-liposome was nano-encapsulated into basil seed gum (BSG) and was incorporated into the ricotta cheese formulation in two forms of free and nano-capsules in two levels of 3% and 5% w/w. The measurements were conducted during a 15-day storage period at 4-6°C. The results showed that the titratable acidity, hardness, and chewiness of cheeses were increased and the pH, moisture, total phenol content (TPC), and antioxidant activity were decreased (p < .05). With the addition of BSE concentration, the TPC and antioxidant activity increased significantly (p < .05) and applying the nano-encapsulation method for BSE led to better preservation of bioactive compounds. Based on the rheological results, viscoelastic solid behavior and a weak gel were observed in all cheese samples. The results of sensory evaluation demonstrated that cheeses containing free extract had lower flavor and overall acceptability scores than other samples, which indicates that the nano-encapsulation covered the undesirable flavor of the BSE. Generally, during the 15-day cold storage period, the highest sensory acceptance and functional activity were related to the samples containing nano-encapsulated BSE, especially at the 5% level.

Incorporation of Blue Honeysuckle Juice into Fermented Goat Milk: Physicochemical, Sensory and Antioxidant Characteristics and In Vitro Gastrointestinal Digestion

The addition of fruit juice may improve the physicochemical and functional characteristics of dairy products. The study evaluated the effect of 1−6% (v/v) blue honeysuckle juice (BHJ) on the physicochemical, sensory and antioxidant characteristics of fermented goat milk (FGM) during 21 days of refrigerated storage and in vitro gastrointestinal digestion. The incorporation of BHJ significantly increased (p < 0.05) the water-holding capacity, viscosity, redness (a*) value, total phenolic content (TPC) and ferric ion-reducing antioxidant power during storage. Additionally, BHJ affected the microstructure and sensory score of the samples. FGM treated with 4% (v/v) BHJ exhibited the highest overall acceptability. The supplementation of BHJ diminished the goaty flavor and promoted in vitro protein digestion. Furthermore, the TPC was enhanced in addition to the antioxidant activity of FGM containing BHJ throughout the in vitro digestion. Therefore, FGM supplemented with BHJ serves as a novel and attractive goat dairy product.

Comparison of whole goat milk and its major fractions regarding the modulation of gut microbiota

BACKGROUND

Goat milk can be important for human nutrition because of its nutritional value, which may be attributed to its richness in protein, lactose, fat, and other bioactive components. This study compared the diversity and composition of gut microbiota in response to whole goat milk and its major fractions (milk fat, casein, milk whey, whey protein, and whey supernatant). Goat milk, its major fractions, and sterile distilled water (for the control group) were administered to mice intragastrically, and gut microbiota were compared in these groups using metagenomic analysis.

RESULTS

We observed distinct patterns of gut microbiota from different diet groups. The sample distance heatmap showed that, compared with other goat milk fractions, gut microbiota in the casein group was more similar to that in the whole goat-milk group. The relative abundance of the genus Lactobacillus increased significantly after whole goat-milk treatment; the milk whey fraction increased the abundance of Blautia; milk fat and milk whey related fractions treatment promoted the population of Bacteroides. The network analysis showed that genera Lactobacillus and Lactococcus were negatively associated with Helicobacter and Acinetobacter, respectively.

CONCLUSION

Fractions of goat milk could contain different gut microbiota from whole goat milk. Consumption of certain goat milk fractions could increase the ingestion of beneficial bacteria and inhibit the growth of some pathogenic bacteria. Our results could provide the basis for the research into and development of goat-milk based functional foods. © 2021 Society of Chemical Industry.

Changes of antibiotic resistance genes and gut microbiota after the ingestion of goat milk

Antibiotic resistance genes, as newly emerging contaminants, have become a serious challenge to public health through the food chain. The gut of humans and animals is an important reservoir for the development and dissemination of antibiotic resistance genes because of the great abundance and diversity of intestinal microbiota. In the present study, we evaluated the influence of goat milk on the diversity and abundance of antibiotic resistance genes and gut microbial communities, especially pathogenic bacteria. Male mice were used, 12 for each of the 2 groups: a control group that received sterile distilled water and a treated group that received goat milk, and gut microbiota and antibiotic resistance genes were compared in these groups using metagenomic analysis. The results revealed that ingestion of goat milk decreased the diversity and abundance of antibiotic resistance genes in the mice gut. The relative abundance of fluoroquinolone, peptide, macrolide, and β-lactam resistance genes in the total microbial genes significantly decreased after the intervention. Goat milk intake also significantly reduced the abundance of pathogenic bacteria, such as Clostridium bolteae, Clostridium symbiosum, Helicobacter cinaedi, and Helicobacter bilis. Therefore, goat milk intake might decrease the transfer potential of antibiotic resistance gene to pathogenic bacteria in the gut. In addition, bacteria with multiple resistance mechanisms accounted for approximately 4.5% of total microbial communities in the control group, whereas it was not detectable in the goat milk group, indicating the total inhibition by goat milk intake. This study highlights the influence of goat milk on antibiotic resistome and microbial communities in the gut, and provides a new insight into the function of goat milk for further study.

Functional dairy products as a source of bioactive peptides and probiotics: current trends and future prospectives

Milk is an incredibly healthy food world-wide. However, the 'lactase deficient' individuals cannot digest milk's carbohydrate lactose. A large part of the world population is depriving of highly beneficial milk proteins like casein, lactoalbumin, lactoglobulin, etc. due to lactose intolerance. Production of functional foods and bioactive peptides from milk with natural antioxidants and the addition of probiotics could be the best alternative to extend the use of milk functionalities. Among different probiotics, the lactic acid bacteria (LAB) like Lactobacillus delbrueckii sub sp. bulgaricus, Streptococcus thermophilus and some species of Bifidobacteria and their metabolites (paraprobiotics and postbiotics) have been given more preference to add in milk-derived functional foods. These species are generally considered as heat-tolerant, highly proteolytic, and peptidolytic towards milk proteins and they liberate smaller molecules of bioactive peptides during fermentation and other processes that stimulate the enzyme lactase to help people in digestion of milk carbohydrate lactose. Moreover, the incorporation of natural antioxidants in yoghurt and other dairy products prevents the rancidity of milk fat. The level of bioactive peptides produced in milk-derived functional foods can be determined by capillary zone electrophoresis, mass spectrometry, fractionation, and other modern assessment techniques. Commercial production of functional probiotic products with bioactive peptides could significantly contribute to reduce milk spoilage, enhance health benefits as well as the growth of the agro-processing industry.

Formulation and characterization of yogurt prepared with enzymatically hydrolyzed potato powder and whole milk powder

This study highlights the optimization of a suitable amount of enzymatically hydrolyzed potato powder (EHPP) with whole milk powder (WMP) to produce a quality yogurt. The yogurt was prepared with different levels of EHPP (0, 10, 15, 20, 25, 35 and 50% w/w) with WMP and evaluated after 24 h at 4 °C. The resulted product was analyzed on the basis of physicochemical, sensory, texture, antioxidant activity and microbiological analysis. The prepared yogurt showed a significant (p < 0.05) decrease in pH, protein and fat while acidity, moisture and ash contents were increased compared with control yogurt. In addition, textural parameters like hardness and adhesiveness were decreased while no significant (p < 0.05) change was found in springiness and cohesiveness. Moreover, color parameters such as L ^* and a ^* values decreased while b ^* values were increased. The current study suggested that the yogurt sample supplemented with 25% EHPP of WMP certainly improved the physicochemical, texture, microstructure, color, antioxidant and sensory properties of yogurt with EHPP. The prepared yogurt with EHPP provided an excellent flavor, satisfying sweetness, and homogeneous texture. The yogurt prepared from the EHPP presented potential industrial applications.

SUPPLEMENTARY INFORMATION

The online version contains supplementary material available at 10.1007/s13197-021-05112-6.

The Potential of Olive Leaf Extract as a Functional Ingredient in Yoghurt Production: The Effects on Fermentation, Rheology, Sensory, and Antioxidant Properties of Cow Milk Yoghurt

BACKGROUND

Yoghurt has been traditionally consumed for its high nutritional value and health-promoting benefits. The addition of plant extracts as a source of phenolic compounds and bio-flavonoids has attracted much attention recently since milk and dairy products are deficient in these health-protecting components. Accordingly, olive leaf extract (OLE) has been considered due to the presence of bioactive compounds, primarily polyphenols. Thus, the aim of this research was to investigate the possibility of adding OLE into cow milk yoghurt as a potential functional ingredient.

METHODS

Yoghurts enriched with OLE (1.5, 3, and 5% v/v) were produced and compared with yoghurt without OLE. In all samples acidity, viscosity, colour, syneresis, water holding capacity (WHC), microbiological parameters, sensory properties, total phenols, and antioxidant activity (DPPH and FRAP methods) were determined.

RESULTS

The addition of OLE resulted in shorter fermentation and lower pH, but it had no adverse effect on the viability of yoghurt starter bacteria. OLE-enriched yoghurts showed increased syneresis, higher total phenols content, and antioxidant activity, while WHC and viscosity decreased. Sensory properties were slightly poorer for yoghurts containing higher OLE concentrations. Considering all of the obtained results, the addition of 1.5% OLE appeared to be optimal.

Source-dependent variation in phenolic compounds and antioxidant activities of Prinsepia utilis Royle fruits

Prinsepia utilis, a wild-growing Himalayan shrub, is a good source of phytoceuticals, cosmeceuticals, and antioxidants. The present study is an attempt to investigate the effect of altitude and edaphic factors on phenolics and antioxidant activity in fruit pulp of Prinsepia utilis. The ripened fruits and soil samples were collected for detailed investigation. The fruits (pulp) were extracted in methanol for analyzing total phenolics and antioxidant activity using a spectrophotometric method and phenolic compounds by high-performance liquid chromatography (HPLC). Similarly, standard methods for soil analysis were used. Results reveal that altitude negatively correlated with total phenolics and flavonoid contents determined by a spectrophotometric method and with specific phenolic compounds determined by HPLC. For instance, Dwarahat population (PU-1) at lower altitude (1400 m asl) exhibited higher values of total phenolics and flavonoids, while total tannin was higher at Nainital (PU-6) population (2000 m asl). The antioxidant activity measured by 2, 2-azinobis (3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) was found higher in Narayan Ashram (PU-9) population (2750 m asl), while ferric reducing antioxidant power (FRAP) was significantly higher in Badechena (PU-2) population (1600 m asl). Soil nutrients (edaphic factors) showed a good correlation among measured parameters. Neighbor-joining and principal component analysis identified phenolics and antioxidant-rich populations that can be utilized for collection of fruits from these populations.

Incorporation of phenolic-rich ingredients from integral valorization of Isabel grape improves the nutritional, functional and sensory characteristics of probiotic goat milk yogurt

This study elaborated different probiotic goat milk yogurt formulations with addition of a low-calorie Isabel "Precoce" grape preparation and flour from derived solid by-products. Physicochemical characteristics, probiotic counts, phenolic and protein/peptide molecular weight profile, antioxidant capacity (AC) and sensory acceptance of different yogurt formulations were evaluated. Yogurts with Isabel grape ingredients (IGI) had high nutritional value, distinct phenolic profile and high AC. High counts of probiotic Lactobacillus acidophilus La-05 were found in yogurts during storage. AC of yogurts with IGI increased during a simulated gastrointestinal digestion with breakdown of high molecular weight proteins and release of protein-bound phenolics. AC of yogurts with IGI should be linked to goat milk peptides and Isabel grape phenolics. Yogurts with IGI had enhanced sensory acceptance. Incorporation of Isabel grape preparation and derived by-product flour into probiotic goat milk yogurt resulted in an added-value product with multifunctional characteristics and improved sensory characteristics.

Chemical composition, quality attributes and antioxidant activity of stirred-type yogurt enriched with Melastoma dodecandrum Lour fruit powder

Incorporation of Melastoma dodecandrum Lour fruit powder as a promising functional ingredient for stirred-type yogurt (STY) improved physicochemical properties, polyphenol contents, antioxidant activity, microstructure, and texture of STY.

Hydrogen sulfide treatment increases the antioxidant capacity of fresh Lingwu Long Jujube (Ziziphus jujuba cv. Mill) fruit during storage

Hydrogen sulfide (H₂S) has been identified as an important gaseous signal molecule in plants. Here, we investigated the effects of H₂S on postharvest senescence and antioxidant metabolism of Lingwu Long Jujube (Ziziphus jujuba cv. Mill) fruits (LLJF). Fumigation of Jujube fruits with H₂S released from 0.4 mm NaHS could significantly prolong the postharvest shelf life of jujube fruits, reduce the decay rate of fruit, the weight loss of fruit, and inhibit the fruit loss, hardness, color, soluble solids, and titratable acidity. Compared with the control group, exogenous H₂S fumigation significantly decreased the loss of chlorophyll, carotenoids, soluble protein, ascorbic acid, phenols, and flavonoids in jujube fruits during post-harvest storage. At the same time, H₂S could significantly delay the accumulation of malondialdehyde (MDA), hydrogen peroxide (H₂O₂) and superoxide anion (O₂^∙−) and promote catalase (CAT), superoxide dismutase (SOD), ascorbate peroxidase (APX), peroxidase (POD) activity, and inhibit polyphenol oxidase (PPO) activity. To summarize, H₂S can effectively alleviate postharvest senescence and decay of jujube fruits by regulating the ROS accumulation and antioxidant enzymes, and prolong the storage period of postharvest.

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H₂S treatment could significantly prolong the postharvest shelf life of jujube fruits.

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H₂S could significantly delay the accumulation of MDA, H₂O₂ and O₂^∙− during storage of jujube fruits.

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H₂S treatment promote CAT, SOD, APX, POD activity, and inhibit PPO activity during storage of jujube fruits.

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Provides a new method for storage of post-harvest jujube fruits.