Probiotic Mascarpone-type cheese: Characterisation and cell viability during storage and simulated gastrointestinal conditions

Short-communication: Study of fatty acid metabolites in microbial conjugated fatty acids-enrichment of milk and discovery of additional undescribed conjugated linolenic acid isomers

Microbially enriched food in conjugated linoleic (CLA) and conjugated linolenic (CLNA) acids is intensively studied nowadays. The conversion of linoleic (LA) and α-linolenic acids (α-LNA) into these compounds may involve different fatty acid (FA) intermediates. This research aimed to investigate potential FA byproducts in milk during microbial CLA/CLNA-enrichment using Bifidobacterium breve DSM 20091. Milk fermented with pure α-LNA showed a decrease in free myristic acid, while pure LA led to an increase in free stearic acid. No additional FA compounds were found alongside CLA/CLNA isomers. The strain produced several CLA isomers from LA, but only when administered alone. Nonetheless, when α-LNA was assayed, additional CLNA isomers, never reported before for bifidobacteria, were observed. In conclusion, except for stearic acid in the presence of LA, no side-FA metabolites were released during milk microbial CLA/CLNA-enrichment. Results suggest either CLA/CLNA production occurs in one single-step or intermediates biotransformation is very fast.

What are the main obstacles to turning foods healthier through probiotics incorporation? a review of functionalization of foods by probiotics and bioactive metabolites

Functional foods are gaining significant attention from people all over the world. When added to foods, probiotic bacteria can turn them healthier and confer beneficial health effects, such as improving the immune system and preventing cancer, diabetes, and cardiovascular disease. However, adding probiotics to foods is a challenging task. The processing steps often involve high temperatures, and intrinsic food factors, such as pH, water activity, dissolved oxygen, post-acidification, packaging, and cold storage temperatures, can stress the probiotic strain and impact its viability. Moreover, it is crucial to consider these factors during food product development to ensure the effectiveness of the probiotic strain. Among others, techniques such as microencapsulation and lyophilization, have been highlighted as industrial food functionalization strategies. In this review, we present and discuss alternatives that may be used to functionalize foods by incorporating probiotics and/or delivering bioactive compounds produced by probiotics. We also emphasize the main challenges in different food products and the technological characteristics influencing them. The knowledge available here may contribute to overcoming the practical obstacles to food functionalization with probiotics.

Lactic acid bacteria viability in different refrigerated food matrices: a systematic review and Meta‑analysis

The aim of this systematic review and meta-analysis was to determine which variables affect the viability of lactic acid bacteria (LAB) added to different types of refrigerated foods during the first 28 days. Scopus, ScienceDirect, PubMed and Cochrane Central Register of Reviews databases were searched from 1997 to April 2022. A total of 278 studies, which showed randomized and controlled experiments published in peer reviewed journals, were included. The viability of LAB in different moments during the storage process was synthesized as mean point estimate (MPE) via random-effects meta-analyses and the effect of multiple factors on the LAB´s viability was evaluated by multiple meta-regression. The meta-analysis showed that the decrease in LAB viability will be more abrupt the greater the initial dose. The physical structure of food may influence bacterial viability. Fruit was the type of product that most quickly lost viability. Co-culture of two or more species did not affect viability. Preservation methods had an unfavorable effect and prebiotics had a beneficial effect on bacterial viability. Viability was genus dependent. The data obtained in this study provide an overview of the factors to be taken into account for the design of new foods.

Preparation and Characterization of Novel Chitosan Coatings to Reduce Changes in Quality Attributes and Physiochemical and Water Characteristics of Mongolian Cheese during Cold Storage

The objective of this study was to evaluate the effect of O-carboxymethyl chitosan coating on microbiological, physiochemical, and water characteristics of Mongolian cheese during refrigerated storage. O-carboxymethyl chitosan coatings, particularly at 1.5%, improved cheese preservation by significantly inhibiting microbial growth, reducing changes in protein and non-protein nitrogen, and preserving pH and titratable acidity. For texture profile analysis (TPA), the hardness, gumminess, and chewiness in O-CMC treatments were significantly more stable than those in the control during storage. In addition, the relaxation component and image of nuclear magnetic resonance (NMR) were used to analyze the internal water mobility of the cheese during storage. Compared with other treatments, the 1.5% O-carboxymethyl chitosan coating had the best overall preserving effect during storage. O-carboxymethyl chitosan coating could be used in cheese preservation applications and could extend the shelf life of Mongolian cheese. The cheese coated with 1.5% O-carboxymethyl chitosan coating ranked the highest in acceptability at the end of the storage period.

Study of the viability of using lipase-hydrolyzed commercial vegetable oils to produce microbially conjugated linolenic acid-enriched milk

This work studied the viability of using vegetable oils as precursor substrates to develop a dairy product enriched in microbial conjugated linoleic (CLA) and conjugated linolenic (CLNA) acids. Hydrolysis of hempseed, flaxseed (FSO) and soybean (SBO) oils was tested with Candida rugosa (CRL), Pseudomonas fluorescens, or Pancreatic porcine lipases. FSO and SBO, previously hydrolyzed with CRL, were further selected for cow's milk CLA/CLNA-enrichment with Bifidobacterium breve DSM 20091. Thereafter, higher substrate concentrations with hydrolyzed FSO were tested. For all tested oils, CRL revealed the best degrees of hydrolysis (>90 %). Highest microbial CLA/CLNA yield in milk was achieved with hydrolyzed FSO, which led to the appearance of mainly CLNA isomers (0.34 mg/g). At higher substrate concentrations, maximum yield was 0.88 mg/g CLNA. Therefore, it was possible to enrich milk with microbial CLNA using vegetable oil, but not with CLA, nor develop a functional product that can deliver a reliable effective dose.

Occurrence of Listeria spp. in Soft Cheese and Ice Cream: Effect of Probiotic Bifidobacterium spp. on Survival of Listeria monocytogenes in Soft Cheese

Listeria monocytogenes is one of the most important emerging foodborne pathogens. The objectives of this work were to investigate the incidence of Listeria spp. and L. monocytogenes in soft cheese and ice cream in Assiut city, Egypt, and to examine the effect of some probiotic Bifidobacterium spp. (Bifidobacterium breve, Bifidobacterium animalis, or a mixture of the two) on the viability of L. monocytogenes in soft cheese. The existence of Listeria spp. and L. monocytogenes was examined in 30 samples of soft cheese and 30 samples of ice cream. Bacteriological analyses and molecular identification (using 16S rRNA gene and hlyA gene for Listeria spp. and L. monocytogenes, respectively) were performed on those samples. Additionally, Bifidobacterium spp. were incorporated in the making of soft cheese to study their inhibitory impacts on L. monocytogenes. Out of 60 samples of soft cheese and ice cream, 25 samples showed Listeria spp., while L. monocytogenes was found in only 2 soft cheese samples. Approximately 37% of soft cheese samples (11 out of 30) had Listeria spp. with about 18.0% (2 out of 11) exhibiting L. monocytogenes. In ice cream samples, Listeria spp. was presented by 47% (14 out of 30), while L. monocytogenes was not exhibited. Moreover, the addition of B. animalis to soft cheese in a concentration of 5% or combined with B. breve with a concentration of 2.5% for each resulted in decreasing L. monocytogenes efficiently during the ripening of soft cheese for 28 d. Listeria spp. is widely found in milk products. Probiotic bacteria, such as Bifidobacterium spp., can be utilized as a natural antimicrobial to preserve food and dairy products.

Effects of the probiotic bacteria on the quality properties of mozzarella cheese produced from different milk

The aim of the study was evaluating the effect of probiotic bacteria on chemical values, texture profile and sensory attributes of Mozzarella cheese which produced from cow and buffalo milk during the storage. The acidity, dry matter content, amount of protein and ripening index of sample increased throughout the storage (P < 0.05). Storage time influenced acidity, dry matter content, amount of protein and ripening index of samples (P < 0.001). Lightness and redness decreased while yellowness increased (P < 0.05). Storage time influenced lightness and yellowness of samples (P < 0.001). TPA parameters increased. The count of Lactobacillus acidophilus increased during the storage (P < 0.05) but Bifidobacterium lactis spp. animalis count increased first 14 days of storage and later decreased (P < 0.05). The samples produced from buffalo milk by adding probiotic bacteria had the highest sensory scores.

Quinoa flour as a skim milk powder replacer in concentrated yogurts: Effect on their physicochemical, technological, and sensory properties

Milk standardization with solids (i.e., nonfat milk solids, MSNF) for yogurt manufacture is traditionally achieved by the addition of skim milk powder (SMP). However, the addition of SMP to milk‐based yogurt increases lactose content and decreases both protein content and gel firmness. Thus, in this work, quinoa flour (QF; 0%, 25%, 50%, 75%, and 100% w/w) was used to replace SMP in concentrated yogurt. The physicochemical, textural, and sensory properties and microstructure of the yogurt were evaluated during cold storage. Generally, protein content, water‐holding capacity, and L* value decreased, while syneresis, textural attributes, and viscosity increased with increasing QF content. The substitution of high levels of QF (>25%, w/w) for SMP led to significantly shorter fermentation times, as compared to the control sample. The scanning electron microscopy observations showed significant changes in the yogurt microstructure as a consequence of QF replacement. Samples with 25% (w/w) substitution of QF and control had the highest scores in overall acceptance. According to the results, QF could be applied as an interesting raw material for concentrating the milk‐based yogurt at substitution level of 25% (w/w).

Probiotic Supplementation and Food Intake and Knowledge Among Patients and Consumers

The consumption of probiotics has gained popularity, highlighting the importance for consumers and clinicians to be aware of their compositions and health effects. The primary objective was to determine incentives for taking probiotics and knowledge about probiotic composition among consumers of various education levels, ethnicities, and locations. A secondary objective was to determine brands, dosages, prices, advertised benefits, and refrigeration status of commercially available probiotics in the Sacramento region. This was a voluntary anonymous online survey conducted from May to August 2017. Surveys were administered at the University of California Davis (UCD) Dermatology Clinic, as well as at approved locations within a 100-mi. radius. Data analysis was performed at the UCD Dermatology clinic. Eligible participants age 18 years and older were asked to complete a voluntary anonymous online survey. A random sample of participants were recruited from the UCD Dermatology clinic, local schools, and health food stores within the designated parameters. We collected 396 surveys, 97% of which were completed. Of those surveyed, 39.4% have previously taken probiotics, 44.6% could identify at least one species present in their supplement, 42.5% could identify the number of strains, and 33.0% could identify the dosage. Gut health was the most common reason for taking probiotics (58.1%). Most rated price as important when purchasing probiotics (70.3%). Although probiotic use is prevalent in Sacramento, most people are unfamiliar with the composition of their supplement. More evidence is needed to guide consumers in making more educated decisions.

Encapsulation of Bifidobacterium bifidum by internal gelation method to access the viability in cheddar cheese and under simulated gastrointestinal conditions

The current study was conducted to elucidate the impact of encapsulation on the stability and viability of probiotic bacteria (Bifidobacterium bifidum) in cheddar cheese and in vitro gastrointestinal conditions. Purposely, probiotics were encapsulated in two hydrogel materials (kepa carrageenan and sodium alginate) by using an internal gelation method. Cheddar cheese was supplemented with unencapsulated/free and encapsulated probiotics. The product was subjected to physicochemical (pH, titrable acidity, moisture, and protein) and microbiological analysis for a period of 35 days of storage. Furthermore, the probiotics (free and encapsulated) were subjected to simulated gastrointestinal conditions. The initial probiotic count in cheese containing encapsulated probiotic was 9.13 log CFU/g and 9.15 log CFU/g which decreased to 8.10 log CFU/g and 7.67 log CFU/g while cheese containing unencapsulated probiotic initially 9.18 log CFU/g decreased to 6.58 log CFU/g over a period of 35 days of storage. The incorporation of unencapsulated and encapsulated probiotic affected the physicochemical, microbiological, and sensory attributes of the cheese. The encapsulated probiotic bacteria exhibited better survival as compared to unencapsulated probiotic. A 2.60 CFU/g log reduction in unencapsulated cells while just 1.03 CFU/g and 1.48 CFU/g log reduction in case of sodium alginate and K-carrageenan, respectively, was recorded. In short, encapsulation showed protection and stability to probiotic in hostile conditions.

Technological Properties of Bifidobacterial Strains Shared by Mother and Child

Technological processes in the dairy industry and the further passage through the gastrointestinal tract could impair viability and functionality of probiotic bifidobacteria. In the present work, the growth in milk of nine bifidobacterial strains shared by mother and child, their survival to freeze-drying and cold storage, and their behavior in a model cheese were investigated. All the strains exhibited high stability to the technological conditions studied when compared with two commercial strains. Bifidobacterium breve INIA P734 and Bifidobacterium bifidum INIA P671 as adjunct cultures maintained high stability during manufacture and ripening of cheese. Both strains showed, at the end of ripening period, resistance to simulated gastrointestinal conditions. Moreover, their presence did not affect negatively the quality of cheese. B. breve INIA P734 and B. bifidum INIA P671 could be considered as potential candidates for their use in cheese as adjunct cultures.