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This paper aims to study the effect of addition of green banana flour (GBF) in skim milk, provides a nutritional and functional contribution to this matrix when added. They have biological compounds like resistant starch, phenolic compounds, antioxidant compounds and others. The skim milk containing 1.08 per cent of GBF was chosen after a central composite rotational design and response surface methodology. The response variable was the growth of Lactobacillus plantarum (LP) and Lactobacillus helveticus (LH).

During the fermentation process, the antioxidant activity, plasmid DNA protection capacity, proteolytic activity and inhibitory activity of angiotensin-converting enzyme (ACE) of the fermented milk was determined.

All variables were influenced by the fermentation time. The antioxidant activity evaluated by the ABTS radical presented values of 0.83 ± 0.04 µM Trolox.mL−1 and 0.79 ± 0.02 µM Trolox.mL−1, respectively, for the fermented LP and LH. The extracts fermented by L. plantarum and L. helveticus were able to inhibit the oxidation of plasmidial DNA. The proteolytic activity was higher in the fermented with LH (1.16 ± 0.03) than in the fermented with LP (0.71 ± 0.02). The ACE inhibitory activity was higher in the fermented LH (59.01 per cent) than in the fermented LP (54.45 per cent).

Fermented milk with 1.08 per cent GBF presented positive results in the analyzed variables and could be studied commercially as a functional food alternative.

Kefir is a traditional fermented dairy beverage that has numerous health benefits due to the presence of bacteria and yeasts in an exopolysaccharide matrix. This study aims to isolate and identify beneficial microorganisms and evaluate the antimicrobial activity of kefir beverage against two important food-borne pathogens including Salmonella Typhimurium and Listeria monocytogenes.

Microorganisms were identified by the polymerase chain reaction with specific primers, and antimicrobial activity was evaluated by the disk diffusion method.

The following microorganisms were identified as natural inhabitants of the kefir grains: Leuconostoc lactis, Lactococcus lactis subspecies lactis, Streptococcus cremoris, Enterococcus faecalis, Enterococcus faecium, Lactobacillus helveticus, Leuconostoc mesenteroides, Lactobacillus fermentum, Lactobacillus reuteri, Lactobacillus plantarum, Lactobacillus casei, Bifidobacterium langum, Saccharomyces cerevisiae and Pichia fermentas. Also, the results obtained from the disk diffusion method showed the inhibitory effect of kefir milk on Salmonella Typhimurium and Listeria monocytogenes with an inhibitory average diameter of 8.3 ± 4–9.1 ± 2.8 and 3.4 ± 3–6.6 ± 3 mm, respectively.

The results of this study showed that Iranian traditional kefir beverage contained different species of lactic acid bacteria and yeasts and has antimicrobial activity against two important food-borne pathogens, Salmonella Typhimurium and Listeria monocytogenes, which the highest inhibitory effect was observed against Salmonella Typhimurium.

The purpose of the paper is to show that traditionally, kefir was obtained by fermenting milk with kefir grains. Wide variation in microflora of kefir grains makes it difficult to obtain an optimal and uniform starter culture necessary for obtaining a quality kefir. Reviewed literature on microbiological and technological innovations in kefir production would enrich the scientific knowledge resulting in production of kefir with superior physical, chemical, nutritional, therapeutic and sanitary qualities.

An attempt is made to highlight the microbiological and technological aspects of kefir production with regard to the microflora of kefir grains, suitability of different types of milk, treatment of milk, starter inoculation and incubation, packaging, storage and post‐production treatment of kefir as well as methods of preservation of kefir grains.

Diverse microflora of kefir grains is the prime cause for the wide variation in kefir quality. Production of kefir is based on symbiotic relation between lactic acid bacteria and yeasts and the type of milk, their heat‐treatment, size of inoculating starters and temperature of incubation influence their metabolic activities. Application of a suitable combination of lactic acid bacteria and yeasts would enable production of kefir with more uniform product with specific properties Packaging of kefir in a suitable container and storage at low temperature are suggested to retain its qualities.

Fermentation of milk with a suitable starter combination consisting of lactic acid bacteria and yeasts rather than application of kefir grains during the production of kefir would be more scientific to yield a product with enhanced nutritional and therapeutic qualities.

This study aims to investigate the antihypertensive effect of camel milk hydrolysate in rats with fructose-induced hypertension.

The antihypertensive effect of fermented camel milk was determined using 6 groups comprising 36 Wistar male rats. Blood pressure of rats was altered via exposure to a 10% fructose (w/v) diet in drinking water for 3 weeks before conducting 21 days of treatment. The authors conducted the experiment for short and long term using different doses of 800 and 1,200 mg/kg body weight. Serum was used to assay total cholesterol (TC), triglyceride (TG), glucose and insulin levels using standard biochemical kits.

The group that received 1,200 mg hydrolysate camel milk (HM) has significantly (p = 0.003) reduced systolic and diastolic blood pressure after a short exposure time (4–8 h). These effects were significantly (p = 0.005) comparable to the nifedipine (NIF) drug group. Similar long-term (21 days) effects on blood pressure were observed in 1,200 mg HM and NIF groups. Angiotensin-converting enzyme (ACE) activity and levels were also reduced in a correlation with blood pressure reduction only in HM1200 and HM800 treated groups. The authors observed no significant effect on blood pressure in groups receiving the 800 mg HM or 1,200 mg unhydrolyzed camel milk (UM). Rats receiving the 10% fructose diet showed significant differences from control rats regarding their blood biochemistry, including TG, TC, blood glucose and insulin levels. Rats in groups NIF, HM1200 and HM800 showed a significant (p < 0.05) reduction in serum glucose, insulin, TG and TC levels toward the baseline level.

Further mechanistic investigation on the HM antihypertensive activity is highly recommended before suggesting HM as a product to reduce blood pressure. While drug–food interaction between HM and antihypertensive drugs, especially ACE inhibitors, is probable, UM seems not to affect blood pressure or ACE activity and therefore is expected to have no or minimal effects on the activity of other antihypertensive drugs. Investigation of ACE expression from various organs including lungs and leukocytes is highly recommended in future works using sodium dodecyl-sulfate polyacrylamide gel electrophoresis and western blot analysis or reverse transcription polymerase chain reaction.

No previous studies have measured the antihypertensive activity of milk hydrolysate mediated by the reduction of ACE activity and levels in plasma. Mechanisms involved in attenuating the levels of ACE warrant further investigation.

The purpose of this study was to investigate the chemical, textural and sensory properties of some starter cultures fruit-added Golot cheese.

Six types of Golot cheeses were produced in this study. While the control sample contained no starter cultures, five different starter culture combinations (GS1: Streptococcus thermophilus, Lactococcus lactis subsp. cremoris, L. lactis subsp. lactis and Lactobacillus bulgaricus; GS2: S. thermophilus and L. bulgaricus; GS3: S. thermophilus; GS4: S. thermophilus and Lactobacillus helveticus; and GS5: S. thermophilus, L. lactis subsp. cremoris and L. lactis subsp. lactis) were applied to the other cheese samples using an immersion technique. Then, all cheeses were vacuum-packed and ripened at 4 ± 1°C for three months and their chemical, biochemical, sensory and textural analyses were performed on the 2nd, 15th, 30th, 60th and 90th days of ripening.

Results indicated that generally starter cultures have positive effects on the chemical, biochemical and sensory properties of Golot cheese. Considering the final values, the addition of starter cultures enhanced the ripening index of Golot cheeses (8.4%–9.2%), except the GS3 (7.4%), compared to the control (8.1%). At the end of the ripening period, meltability values of GS4 (16.5 mm) cultured cheeses were higher than those of other cultured cheeses (13.0–15.5 mm) and control cheese (14.5 mm). While lipolysis values were low in fresh cheese, it increased during ripening. Overall, GS3 (2.46 acid degree value [ADV]) and GS4 (2.40 ADV) had the highest lipolysis rate, while GS1 (2.14 ADV) had the lowest (p = 0.07). Electrophoretograms indicated that the highest fragmentation of α- and ß-casein occurred in GS5 (48.43%) and GS1 (44.24%), respectively. Also, GS5 was the most appreciated and preferred cheese in terms of sensory. Regarding texture, hardness, cohesiveness, adhesiveness, springiness and gumminess values were determined to be statistically important in terms of ripening time and cheese variety (p < 0.01).

Consequently, all starters had a positive impact on Golot cheese samples and among all S. thermophilus and L. helveticus starter were determined to be the most applicable one considering ripening, texture, sensory and melting properties.

There is need for exhaustive studies to be undertaken to identify various probiotic strains and to understand the actual mechanism of action by which these probiotics exert their health benefits in order to exploit its fullest health benefits expressed by various kinds of the probiotic strains. The paper aims to discuss these issues.

The health effects of the probiotics can be accessed by in vivo as well as the in vitro studies of live microorganisms and their biological active compounds on various disease-causing organisms and their harmful metabolites.

The paper is a brief review of recent findings about the health benefits of probiotic strains of microorganisms. The health effects of fermented food items were known since the time immemorial, but the actual cause of this was a mystery. Recent discoveries led to the author's knowledge about the mechanism through which they exert these curative effects which is either by competitive inhibition of harmful microbes in gut or by production of biological active compounds against disease-causing organisms and their harmful metabolites.

Probiotics are commonly consumed as part of fermented foods which are produced with active live cultures, so various new types of these probiotic cultures can be introduced which can act as food as well as curative agents for treating and preventing various types of diseases at nominal costs.

The aim of this study is to examine the bioactive properties of lactobacilli‐fermented B‐vitamin soymilk, namely the in‐vitro antihypertensive property and bioconversion of isoflavone glucosides to aglycones.

Lactobacillus acidophilus BT 1088, L. fermentum BT 8219, L. acidophilus FTDC 8633 and L. gasseri FTDC 8131 were investigated for their bioactive potential and enhanced bioconversion of isoflavones in soymilk supplemented with individual B‐vitamins at a concentration of 1 mg/L.

The supplementation of thiamine, riboflavin, niacinamide, calcium pantothenate, biotin and folic acid enhanced the ACE‐inhibitory activity of lactobacilli in soymilk accompanied by a lower IC₅₀ value compared to the control (P<0.05). The β‐glucosidase specific activity of lactobacilli was also enhanced on supplementation of B‐vitamins, leading to increased bioconversion of isoflavones in soymilk. The concentration of genistein was decreased, accompanied by an increased concentration of genistein on fermentation in the presence of thiamine, niacinamide, biotin, calcium pantothenate and folic acid. Additionally, the supplementation of niacinamide, calcium pantothenate, biotin and folic acid also led to lower concentrations of malonyl daidzin, indicating increased hydrolysis of malonyl daidzin to daidzin. Results from the present study indicated that the supplementation of B‐vitamins could enhance the bioactive potential and bioconversion of isoflavones in lactobacilli‐fermented soymilk.

This work has shown that the supplementation of B‐vitamins in lactobacilli fermented soymilk has exerted in vitro ACE‐inhibitory activity and increased the accumulation of bioactive isoflavone aglycones. To the authors' knowledge, this is the first evaluation reporting on such aspects.

The purpose of this paper is to provide an overview of the antimicrobial and antioxidant properties of postbiotics and the use of postbiotics to increase the shelf life and quality of food.

In this review paper, all articles from five electronic databases containing Google Scholar, Web of Science, PubMed, Scopus and Science Direct were considered and selected according to the purpose of the study.

In addition to improving food safety and increasing its shelf life, natural food preservation using biological preservatives also has a positive effect on improving consumer health. As a result, protection using natural antioxidants and antimicrobial agents seems essential. Postbiotics, having favorable characteristics such as nontoxicity, long shelf life and ease of standardization and transportation, are known as suitable antioxidant and antimicrobial, and there is an interest in making antioxidant and antimicrobial active films containing postbiotics to delay spoilage, increase the shelf life of perishable foods without changing their sensory characteristics.

Postbiotic refers to all soluble factors that are either secreted from living probiotic cells or released after cell lysis. These compounds include enzymes, peptides, polysaccharides, organic acids, teichoic acids and cell surface proteins, and their effects have been proven to improve some human and animal diseases. Probiotic bacteria must survive unfavorable conditions such as processing, storage, distribution, preparation and the digestive system to exert their health-giving effects, whereas their metabolites (postbiotics) have overcome these adverse conditions well and may be a good substitute for probiotics.

Gamma-aminobutyric acid (GABA) is a four-carbon and nonprotein amino acid, made by various microorganisms, especially lactic acid bacteria (LAB) and probiotics. GABA has various physiological roles, for instance, insomnia, depression, hypotensive activity as well as diuretic effects. The production of GABA-based foods is a favorable result from GABA’s biological and functional properties. The purpose of this study is to investigate different methods of improving GABA production in probiotics and LAB to select the superlative method and bacterial strain.

In this review paper, all articles from five electronic databases containing Google Scholar, Web of Science, PubMed, Scopus and Science Direct were considered from 2000 to January 11, 2023, with keywords “Optimization” OR “Enhance” OR “Increase” AND “Gamma-aminobutyric acid” OR “GABA” AND “Probiotics” OR “Lactic acid bacteria” and selected according to the purpose of the study.

It seems that among all the investigated methods, an effective fermentation procedure with optimal conditions including fermentation medium, 5 L; glutamic acid, 295 g/L; incubation temperature, 32°C; inoculum, 10% (v/v); and agitation, 100 rpm, after 48 h of fermentation led to producing 205,800 mg/L of GABA from the effective bacterial strain Lactobacillus brevis NCL912.

With a simple but optimized fermentation, L. brevis NCL912 can be used for the efficient GABA production in the pharmacy and food factories.

Consumer inclination towards probiotic foods has been stimulated due to well-documented evidence of health benefits of probiotic-containing products and consumer demand for natural products. It is assumed that the viability and metabolic activities of probiotics are essential for extending health benefits and for successful marketing of probiotics as a functional food. The purpose of this paper is to demonstrate that even dead or inactivated probiotic cells could extend health benefits, indicating that probiotic viability is not always necessary for exhibiting health benefits.

Attempt has been made to review the literature on the status of probiotic foods available in the world market, their impact on the gut flora and the various factors affecting their viability. Both review and research papers related to efficacy of inactivated, killed or dead probiotic cells towards health benefits have been considered. Keywords used for data search included efficacy of viable or killed, inactivated probiotic cells.

The reviewed literature indicated that inactivated, killed or dead probiotic cells also possess functional properties but live cells are more efficacious. All live probiotic cultures are not equally efficacious, and accordingly, dead or inactivated cells did not demonstrate functional properties to extend health benefits to all diseases.

Capability of non-viable microorganisms to confer health benefits may attract food manufacturers owing to certain advantages over live probiotics such as longer shelf-life, handling and transportation and reduced requirements for refrigerated storage and inclusion of non-bacterial, biologically active metabolites present in fermented milks’ fraction as dried powders to food matrixes may result in the development of new functional foods.