Combined effects of replacement of sucrose with d-tagatose and addition of different probiotic strains on quality characteristics of chocolate milk

Production and Characterization of a Novel Symbiotic Plant-based Beverage Rich in Antioxidant Phenolic: Mung Bean and Rye Sprouts

There is an increasing demand for non-dairy probiotic food due to the constraints associated with dairy probiotics. In this study, a co-culture synbiotic beverage was prepared using a mixture of mung bean and rye sprouts inoculated with Lactobacillus plantarum (B-28) and Lactobacillus casei (B-29), along with inulin and oligofructose as prebiotics. The effects of prebiotic addition and starter culture on the survival of probiotics during cold storage and simulated gastric conditions were examined. Additionally, titratable acidity, pH, phenolic content, antioxidant activity, and sensory characteristics were evaluated over a 28-day period. The resulting product demonstrated good survival for L. casei (107 CFU.ml-1) and L. plantarum (106 CFU.ml-1) after 4 weeks under refrigeration with no significant changes in quality. The samples exhibited significantly high total phenolic content (TPC), ranging from 19.18 to 25.75 mg GAE/100 mL, which L. casei-containing drinks exhibited the highest TPC activity (p < 0.05). All treatments showed a significant reduction in probiotic survival during gastrointestinal digestion in the laboratory conditions (p < 0.05), although more than 50% survival was observed for all strains. The addition of prebiotics to the beverages led to a significant decrease in phenolic content (p < 0.05), but improved sensory scores. The highest turbidity was observed in the sample containing both probiotics and inulin on the 28th day at 38.1 (NTU). In general, the synergistic effect of probiotics was more pronounced when used together with both prebiotics in the beverages compared to their individual use. The results suggest that the production of this beverage could serve as a nutritious alternative to lactose-sensitive dairy beverages and contribute to the development of future probiotic food products.

Development of a functional synbiotic beverage fortified with different cereal sprouts and prebiotics

Abstract

The study was devoted to developing a novel synbiotic beverage based on with millet, rye and alfalfa sprouts with a mixed culture of Lactobacillus casei and Lactobacillus plantarum. In this regard, the influences of incorporated prebiotics inulin and oligofructose on probiotics viability during the refrigerated storage (4 ± 1 °C, 28 days) as well as under the simulated gastric condition were investigated. The characteristics such as microbial viability, physicochemical properties (viscosity, pH, titrable acidity and radical scavenging activity) and sensorial evaluation were assessed. The synbiotic beverage produced contained 10⁸ CFU ml^-1 for L. casei, with a good survival throughout the storage period (10⁸ CFU ml^-1) and L. plantarum at sufficient levels (10⁶ CFU ml^-1) after about 21 days. Inulin and oligofructose promoted the growth of the strains and their viability under cold storage while conferring higher sensory scores. In this context, the beverages demonstrated acceptable sensory attributes. The viability (bacterial survival) of over 55% for all the strains was achieved under simulated gastric condition. Therefore, the introduced fermented beverage was a good food matrix from the viability of probiotics as well as under the gastric condition and sensory characteristics.

Graphic abstract

Development and characterization of probiotic mucilage based edible films for the preservation of fruits and vegetables

There is growing interest among the public and scientific community toward the use of probiotics to potentially restore the composition of the gut microbiome. With the aim of preparing eco-friendly probiotic edible films, we explored the addition of probiotics to the seed mucilage films of quince, flax, and basil. These mucilages are natural and compatible blends of different polysaccharides that have demonstrated medical benefits. All three seed mucilage films exhibited high moisture retention regardless of the presence of probiotics, which is needed to help preserve the moisture/freshness of food. Films from flax and quince mucilage were found to be more thermally stable and mechanically robust with higher elastic moduli and elongation at break than basil mucilage films. These films effectively protected fruits against UV light, maintaining the probiotics viability and inactivation rate during storage. Coated fruits and vegetables retained their freshness longer than uncoated produce, while quince-based probiotic films showed the best mechanical, physical, morphological and bacterial viability. This is the first report of the development, characterization and production of 100% natural mucilage-based probiotic edible coatings with enhanced barrier properties for food preservation applications containing probiotics.

Effect of formulation and heat treatment on 5-hydroxymethylfurfural formation and quality parameters in dulce de leche

This work assessed the effect of formulation and heat treatment on the formation of HMF, non-enzymatic browning and rheology of dulce de leche (DL). Laboratory scale trials were developed with different DL formulas: whole powdered milk, skimmed milk, and lactose-free skimmed milk, and added sucrose, subjected to different processing temperatures (110°C, 120°C, and 130°C). Additionally, an alternative formulation was designed in which half the sucrose was replaced by 50% tagatose. DL samples were compared with three commercial products in terms of water activity, soluble solids content, pH, colour, apparent viscosity, and HMF concentration. HMF formation in DL was mitigated (35%) in a lactose-free formulation by lowering the process temperature. Moreover, HMF formation was reduced up to 80% replacing sucrose by tagatose without affecting the quality parameters (pH, soluble solids, colour, and apparent viscosity). Decrease in processing temperature and the use of tagatose are viable alternatives for HMF mitigation in DL.

The effect of yogurt co-fortified with probiotic and vitamin D on lipid profile, anthropometric indices and serum 25-hydroxi vitamin D in obese adult: A Double-Blind Randomized- Controlled Trial

Vitamin D deficiency can be regarded as one of the overgrowing health problem in all of the world. Evidence from a clinical trial suggested a role for probiotic bacteria in increasing vitamin D. However, probiotic's effect is strain specific and this effect should be confirmed about different strains. The objective was to determine if yogurt fortification with probiotic bacteria, Lactobillus acidophilus La-B5, Bifidobacterium lactis Bb-12 either alone or in combination with vitamin D can be a complementary treatment for vitamin D deficiency. The end-points were vitamin D, cardio metabolic lipid profile, anthropometric indices (weight, height, waist, hip, fat mass, lean body mass) and dietary intake. A 10-week parallel-group, double-blind, randomized and controlled trial was conducted on 140 obese men and women. The participants were randomly allocated to receive 100 grams either 1) plain low-fat yogurt or 2) probiotic yogurt or 3) vitamin D-fortified yogurt or 4) probiotic and vitamin D cofortified yogurt. All groups received low-calorie diet. Vitamin D increased significantly in group 4 (p = .008), group 3 (p = .001) and group 1 (p = .012 with no difference between groups. Vitamin D-fortified yogurt had the most effect size and showed a significant difference versus plain (p = .018) and probiotic yogurt (p = .002). Regarding lipid profile, there were no significant differences between groups. Data from this study does not support the hypothesis that yogurt fortified with probiotic bacteria, Lactobillus acidophilus La-5 and Bifidobacterium lactis Bb-12 either alone or in combination with vitamin D might impose any increasing effect on serum level of vitamin D in comparison with vitamin D-fortified yogurt.

Sugar Reduction in Dairy Food: An Overview with Flavoured Milk as an Example

Owing to the public health concern associated with the consumption of added sugar, the World Health Organization recommends cutting down sugar in processed foods. Furthermore, due to the growing concern of increased calorie intake from added sugar in sweetened dairy foods, the present review provides an overview of different types and functions of sugar, various sugar reduction strategies, and current trends in the use of sweeteners for sugar reduction in dairy food, taking flavoured milk as a central theme where possible to explore the aforementioned aspects. The strength and uniqueness of this review are that it brings together all the information on the available types of sugar and sugar reduction strategies and explores the current trends that could be applied for reducing sugar in dairy foods without much impact on consumer acceptance. Among different strategies for sugar reduction, the use of natural non-nutritive sweeteners (NNSs), has received much attention due to consumer demand for natural ingredients. Sweetness imparted by sugar can be replaced by natural NNSs, however, sugar provides more than just sweetness to flavoured milk. Sugar reduction involves multiple technical challenges to maintain the sensory properties of the product, as well as to maintain consumer acceptance. Because no single sugar has a sensory profile that matches sucrose, the use of two or more natural NNSs could be an option for food industries to reduce sugar using a holistic approach rather than a single sugar reduction strategy. Therefore, achieving even a small sugar reduction can significantly improve the diet and health of an individual.

Consumer rejection threshold, acceptability rates, physicochemical properties, and shelf-life of strawberry-flavored yogurts with reductions of sugar

BACKGROUND

There is an increasing demand for reduced-sugar products due to the worldwide prevalence of obesity, diabetes, and cardiovascular diseases. The aim of this study was to evaluate the effects of sugar (sucrose) reductions on the acceptability, preference, and quality of strawberry-flavored yogurts. A consumer rejection threshold test and an acceptability test (N = 53) were conducted using six yogurt samples with decreasing concentrations of sugar (12-5/100 g). Additional physicochemical tests (pH, °Brix, water-holding-capacity, viscosity, and color) were conducted to examine the quality and shelf-life of strawberry-flavored yogurts with reductions of sucrose during 28 days of storage at 4 °C.

RESULTS

Reduction of sucrose affected the acceptability and physicochemical characteristics of yogurts. The consumer rejection threshold showed that sucrose in strawberry-flavored yogurts could be reduced to 5.25/100 g from an initial concentration of 12/100 g without affecting the preferences of consumers. The 71%-sucrose (8.50/100 g of yogurt) was perceived as the most liked (6.27 using a nine-point hedonic scale) and the most preferred (rank sum = 127.50) yogurt sample. For the physicochemical properties of yogurts, the viscosity (3263-5473 cP) decreased, and the color lightness (80.98-85.44) increased during 28 days of storage at 4 °C.

CONCLUSION

Physicochemical properties and preferences were affected by the reduction of sugar. The consumer rejection threshold analysis showed that sucrose can be reduced to less than half of the initial concentration. These findings are useful to understand consumers' acceptability and shelf-life of yogurts with reduced-sugar formulations in the developing of new products. © 2020 Society of Chemical Industry.

Towards efficient enzymatic conversion of D-galactose to D-tagatose: purification and characterization of L-arabinose isomerase from Lactobacillus brevis

L-arabinose isomerase (L-AI) (EC 5. 3. 1. 4. L-AI) that mediates the isomerization of D-galactose to D-tagatose was isolated from Lactobacillus brevis (MF 465792), and was further purified and characterized. Pure enzyme with molecular weight of 60.1 kDa was successfully obtained after the purification using Native-PAGE gel extraction method, which was a monomer in solution. The L-AI was found to be stable at 45-75 °C, and at pH 7.0-9.0. Its optimum temperature and pH was determined as 65 °C and 7.0, respectively. Besides, we found that Ca²⁺, Cu²⁺, and Ba²⁺ ions inhibited the enzyme activity, whereas the enzyme activity was significantly enhanced in the presence of Mg²⁺, Mn²⁺, or Co²⁺ ions. The optimum concentration of Mn²⁺ and Co²⁺ was determined to be 1 mM. Furthermore, we characterized the kinetic parameters for L-AI and determined the K_m (129 mM) and the V_max (0.045 mM min^- 1) values. Notably, L. brevisL-AI exhibited a high bioconversion yield of 43% from D-galactose to D-tagatose under the optimal condition, and appeared to be a more efficient catalyst compared with other L-AIs from various organisms.

Engineering the l-Arabinose Isomerase from Enterococcus Faecium for d-Tagatose Synthesis

l-Arabinose isomerase (EC 5.3.1.4) (l-AI) from Enterococcus faecium DBFIQ E36 was overproduced in Escherichia coli by designing a codon-optimized synthetic araA gene. Using this optimized gene, two N- and C-terminal His-tagged-l-AI proteins were produced. The cloning of the two chimeric genes into regulated expression vectors resulted in the production of high amounts of recombinant N-His-l-AI and C-His-l-AI in soluble and active forms. Both His-tagged enzymes were purified in a single step through metal-affinity chromatography and showed different kinetic and structural characteristics. Analytical ultracentrifugation revealed that C-His-l-AI was preferentially hexameric in solution, whereas N-His-l-AI was mainly monomeric. The specific activity of the N-His-l-AI at acidic pH was higher than that of C-His-l-AI and showed a maximum bioconversion yield of 26% at 50 °C for d-tagatose biosynthesis, with Km and Vmax parameters of 252 mM and 0.092 U mg^-1, respectively. However, C-His-l-AI was more active and stable at alkaline pH than N-His-l-AI. N-His-l-AI follows a Michaelis-Menten kinetic, whereas C-His-l-AI fitted to a sigmoidal saturation curve.

Influence of commercial culture composition and cow milk to soy milk ratio on the biochemical, microbiological, and sensory characteristics of a probiotic fermented composite drink

In this study, the effects of various ratios of cow milk to soy milk (100:0, 75:25, 50:50, 25:75, and 0:100) and three types of commercial culture composition (ABY-1, MY-720, and YO-Mix 210; all of them containing Lactobacillus acidophilus, Bifidobacterium lactis, and yogurt cultures) on the biochemical, microbiological, and sensory characteristics of a probiotic fermented composite drink during incubation and refrigerated storage were investigated. It was found that the shortest fermentation time, greatest mean pH drop rate, and mean acidity increase rate were related to the 50:50/ABY treatment. 25:75/ABY and 25:75/MY treatments exhibited the highest viability of B. bifidum and/or L. acidophilus at the end of 21 days of refrigerated storage. The influence of the type of starter culture composition on the sensory properties of the final products was not significant. Based on microbial and sensory evaluations, using the 50:50 ratio with each type of culture composition was considered as the most suitable treatment.