Lactic Acid Bacteria Fermentation Research Articles

Effect of lactic acid bacteria fermentation on nutrients and anti-nutrients of African black nightshade and African spider plant

African black nightshade is a leafy vegetable consumed in many parts of Africa. African spider plant is also a very important indigenous leafy vegetable consumed all around Africa. Both the African black nightshade and African spider plant are popular despite their tedious preparation techniques which involve boiling and discarding the first water or a lengthy boiling duration to remove bitterness. However, this preparation technique reduces heat-labile and water-soluble nutrients. Fermentation can be a better alternative processing technique since it has been observed that fermented products have better nutritional content and increased safety. However, there is still limited literature on the effect of fermentation on the nutrients and anti-nutrients content of these vegetables. This study aimed to ferment African black nightshade and African spider plant using Lactobacillus fermentum and Lactococcus lactis cultures and determined the effect of the fermentation on their nutrients and anti-nutrients content. Both vegetables were submerged in a 3% sugar and 3% salt brine solution. Total ash, crude proteins and crude fibres significantly increased in starter culture inoculated vegetables. However, both β-carotene and ascorbic acid were slightly reduced in all fermented batches. Anti-nutrients were significantly reduced in all fermented batches. In conclusion, lactic acid fermentation of these vegetables demonstrated the ability to maintain or increase nutrients while reducing of anti-nutrients.

Effect of adding lactic acid bacteria to maize silage on nutritive quality, fermentation properties and in vitro digestibility

This study aimed to determine the effects of adding lactic acid bacteria to maize silage on the nutritionalf quality, its fermentation properties and its in vitro organic matter digestion (IVOMD). In the study, pre-fermented juices (PFJ) prepared from different water-soluble carbohydrate (WSC) sources at the rate of 5% and commercial homofermentative and heterofermentative lactic acid bacteria (LAB) were added to silages. Groups were designed as (I) control, (II) Glucose-PFJ, (III) Fructose-PFJ, (IV) Sucrose-PFJ, (V) Molasses-PFJ, (VI) Homofermentative LAB (HoLAB) and (VII) Heterofermentative LAB (HetLAB). When the lactic acid bacteria (LAB) count, lactic acid (LA), acetic acid (AA), LA/AA ratio, pH and yeast values of the natural fermented lactic acid bacteria liquids prepared by adding 5% different easily soluble carbohydrate sources to meadow grass fermentation values of the groups were examined, the differences between them were statistically significant. 
 The differences between the groups in the CA, ADF, IVOMD and methane (CH4) values of the silage groups prepared by adding PFJ were found to be statistically significant. The differences in the fermentation characteristics of the silages (pH, ammonia-nitrogen (NH3-N), LA, AA, LA/AA, CO2 and total yeast mold after aerobic stability) were statistically significant. When all parameters were examined, it was concluded that the addition of PFJ, which is prepared by adding 5% fructose to the meadow grass plant, to the maize silage has positive effects on IVOMD, ME, CH4, LA and yeast-mold and can be used instead of commercial inoculants.

Malolactic fermentation of lactic acid bacteria isolated from southern Brazilian red wine.

The objective was to isolate lactic acid bacteria (LAB) from southern Brazil's wines and investigate their potential as starter cultures for malolactic fermentation (MLF) in Merlot (ME) and Cabernet Sauvignon (CS) wines through the fermentative capacity. The LAB were isolated from CS, ME, and Pinot Noir (PN) wines in the 2016 and 2017 harvests and evaluated for morphological (color and shape of the colonies), genetic, fermentative (increase in pH, acidity reduction, preservation of anthocyanins, decarboxylation of L-malic acid, yield of L-lactic acid, and content of reduced sugars), and sensory characteristics. Four strains were identified as Oenococcus oeni [CS(16)3B1, ME(16)1A1, ME(17)26, and PN(17)65], one as Lactiplantibacillus plantarum [PN(17)75], and one as Paucilactobacillus suebicus [CS(17)5]. Isolates were evaluated in the MLF and compared to a commercial strain (O. oeni), as well as a control (without inoculation and spontaneous MLF), and standard (without MLF). CS(16)3B1 and ME(17)26 isolates finished the MLF for CS and ME wines, respectively, after 35 days, similar to the commercial strain, and CS(17)5 and ME(16)1A1 isolates ended the MLF in 45 days. In the sensory analysis, ME wines with isolated strains received better scores for flavor and overall quality than the control. Compared to the commercial strain, CS(16)3B1 isolate obtained the highest scores for buttery flavor and taste persistence. CS(17)5 isolate received the higher scores for a fruity flavor and overall quality and the lowest for a buttery flavor. The native LAB displayed MLF potential, regardless of the year and grape species from which they were isolated.

Effect of Lactobacillus (L. acidophilus NCIB1899, L. casei CRL 431, L. paracasei LP33) fermentation on free and bound polyphenolic, antioxidant activities in three Chenopodium quinoa cultivars.

The application of lactic acid bacteria (LAB) fermentation to the production of probiotic beverages is a common method for modifying the health-related functional characteristics and phytochemical content of such beverages. This study evaluated the effect of fermentation with Lactobacillus acidophilus NCIB1899, Lactobacillus casei CRL 431, and Lactobacillus paracasei LP33 on the total phenolic contents (PCs), flavonoid contents (FCs), phenolic profiles, and antioxidant capacities of the solvent-extractable (free) and cell-wall-bound (bound) fractions in quinoa varying in bran color. Compared with unfermented beverages, LAB fermentation significantly increased the free PCs and free FCs by 15.7%-79.4% and 7.6%-84.3%, respectively. The bound PCs increased, whereas bound FCs decreased in fermented black and red quinoa juice. The increments of procyanidin B2 , protocatechuic acid, p-hydroxybenzaldehyde, rutin, and kaempferol through 30h fermentation exceeded 189%-622%, 13.8%-191%, 55.6%-100%, 48.5%-129%, and 120%-325%, respectively. However, the contents of catechin, procyanidin B1 , and ferulic acid decreased with fermentation. Overall, L. acidophilus NCIB1899, L. casei CRL431, and L. paracasei LP33 strains may be suitable for producing fermented quinoa probiotic beverages. L. acidophilus NCIB1899 was superior for fermentation to L. casei CRL431 and L. paracasei LP33. Red and black quinoa had significantly higher total (sum of free and bound) PC and FC concentrations and antioxidant capacities than white quinoa (p<0.05) because of their higher concentrations of proanthocyanins and polyphenol, respectively. PRACTICAL APPLICATION: In this study, different LAB (L. acidophilus NCIB1899, L. casei CRL431, and L. paracasei LP33) were singly inoculated on aqueous solutions from quinoa to ferment probiotic beverage and to compare the metabolic capacity of LAB strains on nonnutritive phytochemicals (phenolic compounds). We observed that LAB fermentation greatly enhanced the phenolic and antioxidant activity of quinoa. The comparison indicated that the L. acidophilus NCIB1899 strain has the highest fermentation metabolic capacity.

Antioxidant Capacity Changes and Untargeted Metabolite Profile of Broccoli during Lactic Acid Bacteria Fermentation

The purpose of this study was to reveal the changes in total phenolic content and antioxidant capacity of broccoli, and an untargeted metabolomics approach was developed to investigate the effect of lactic acid bacteria fermentation on the metabolome of broccoli florets. The results showed that the total phenolic content and antioxidant capacity significantly increased after fermentation. The untargeted metabolite profile showed that the main chemical components of fermented and unfermented broccoli are lipids and lipid-like molecules, organic acids and derivatives and organoheterocyclic compounds. Univariate and multivariate statistical analyses of the identified metabolites showed some metabolites such as sorbitol are upregulated after fermentation, and that other metabolites such as l-malic acid are downregulated after fermentation. Moreover, metabolite pathway analyses were used to study the identification of subtle but significant changes among groups of related metabolites that cannot be observed with conventional approaches. KEGG pathway analysis showed that metabolites are mainly enriched in the glucagon signaling pathway, pyruvate metabolism, glycolysis/gluconeogenesis and fructose and mannose metabolism after fermentation, compared with raw broccoli. The results of this study can help to further our understanding of the impact of LAB fermentation on bioactivity changes in and the metabolites profile of fermented broccoli, and the application of fermented broccoli in health foods and special dietary foods.

Isolation and Identification of Lactic Acid Bacteria and Their Effects on the Off-odor of Burdocks.

Burdocks have diverse nutritional and pharmacological functions, but their unique odor is unwelcome. Here, the effect and mechanism of lactic acid bacteria fermentation on the off-odor of burdocks were investigated. The sensory evaluation showed that burdocks had earthy, musty, grassy, and pepper odors. 2-Isobutyl-3-methoxypyrazine (IBMP) and 2-secbutyl-3-methoxypyrazine (IPMP) mainly contributed to burdock's unique off-odor and were identified by gas chromatography-mass spectrometry combined with headspace-solid phase microextraction (HS-SPME-GC-MS) and relative odor activity value (ROAV) analysis. Weissella cibaria ZJ-5 from screened strains performed with the strongest ability to remove the off-odor and generate a fragrant odor, as determined by sensory evaluation. When incubated aerobically together with IBMP during fermentation, ZJ-5 degraded IBMP directly from 149.56 ± 0.72 to 71.55 ± 1.81 ng/mL. Additionally, linoleic acid content in fermented burdocks was significantly decreased compared with unfermented burdocks. (E,Z)-2,6-Nonadienal, which mainly contributed to fermented burdock's odor, may have been generated from linoleic acid during ZJ-5 fermentation, through the acid catalysis pathway. It indicated that LAB fermentation could improve burdock odor by degrading off-odor compounds and precursors and by generating new aldehydes.

Lactic acid bacteria as an adjunct starter culture in the development of metabiotic functional turmeric (Curcuma longa Linn.) beverage.

Turmeric (Curcuma longa) is a highly nutritious rhizomatous herbaceous plant with remarkable chemical composition and biologically active compounds. This study aimed to evaluate the turmeric, ginger and lemon blend as a fermentable substrate by lactic acid bacteria to develop a fermented nondairy beverage. Results showed that turmeric blend (turmeric 2% w/v, ginger 1.5% v/v, 5% v/v) was an excellent matrix for lactic acid bacteria growth and fermentation dramatically increased total phenolic, flavonoid content and antioxidants capacities impacting the color and sensory properties. Moreover, the formulated fermented turmeric blend was stable for more than 90 days at 4 °C with a healthy bacterial population and nutraceutical stability. Turmeric beverage also inhibited the growth of Caco-2 and MOLT 4 cancerous cell lines in a dosage and time-reliant manner. This way, lactic acid fermentation can be considered as an appropriate tool for developing turmeric based novel bio-intervention with enhanced bioactivity and antagonistic efficacy against recurring food-borne pathogen in this post-antibiotic era.

Flavor precursors and flavor compounds in Cheddar-flavored enzyme-modified cheese due to pre-enzymolysis combined with lactic acid bacteria fermentation

To improve insufficient taste and imbalanced aroma of enzyme-modified cheese (EMC), pre-enzymolysis followed by lactic acid bacteria (LAB) fermentation was employed in this study. The strategy generated taste compounds by fermentation and released crucial flavor precursors by pre-enzymolysis. Flavor precursors and flavor compounds from each step were measured. Results showed that 45–50 and 15–17 times higher free amino acid (FAA) and free fatty acid (FFA) flavor precursors than the control were respectively achieved based on acceptable bitterness and soapiness during pre-enzymolysis. Pre-proteolysis accelerated fermentation and increased lactic acid, floral and almond aromatic ring compounds from phenylalanine (2.0–15.7 times), and rancid branched acids from leucine (3.2–4.4 times) during fermentation. Pre-lipolysis released massive methyl ketones and fatty acids, but flavor imbalanced, which was improved by promoting short-chain fatty acid production during fermentation. These results provided practical references for producing EMC with authentic Cheddar flavor and new avenues for flavor improvement of EMC.

Effects of Lacticaseibacillus casei fermentation on the bioactive compounds, volatile and non-volatile compounds, and physiological properties of barley beverage

Barley beverage contains many natural nutrients which is suitable for lactic acid bacteria (LAB) fermentation. The aim of this study was to explore the influences of Lacticaseibacillus casei 17301 fermentation on the bioactive ingredients, volatile and non-volatile compounds, and physiological properties of barley beverages. Our results showed that the total polyphenols and flavonoids in fermented barley beverages remarkably increased compared to those in unfermented barley beverages. A total of 63 volatile compounds in fermented barley beverages at the different fermentation stages were detected using headspace solid-phase micro-extraction coupled with gas chromatography-mass spectrometry (HS-SPME-GC-MS), including 17 acids, 16 ketones, 11 aldehydes, and 7 alcohols. Furthermore, untargeted metabolomics analysis-based ultra-performance liquid chromatography quadrupole-time of flight mass spectrometry (UHPLC-QTOF-MS) revealed L. casei 17301 effectively altered the non-volatile compounds, especially indole-3-lactic acid, in barley beverages. Most importantly, the barley beverage fermented with L. casei 17301 had elevated the antioxidant and lipase inhibition activities compared to the unfermented barley beverage. Collectively, L. casei 17301 could ameliorated the functionality and flavor of the barley beverage and the flavor of the product. These results of this study provide a theoretical basis for the development of Lacticaseibacillus-fermented cereal products with beneficial physiological properties.

Therapeutic and Dietary Support for Gastrointestinal Tract Using Kefir as a Nutraceutical Beverage: Dairy-Milk-Based or Plant-Sourced Kefir Probiotic Products for Vegan and Lactose-Intolerant Populations

Kefir is a fermented milk beverage different in consistency and taste from other popular milk-product yogurt. Unlike yogurt prepared using lactic acid bacteria in fermentation, milk is fermented for kefir production using preculture in the form of kefir grains. Therefore, the metabolic activities of a mixed culture, including strains of bacteria and yeast, contribute to the probiotic characteristics in kefir. This article is based on the review of published studies on the functionality and nutraceutical properties of kefir. The therapeutic and dietary properties of kefir beverage and its probiotic strains have been discussed for their several health benefits. Concise selected information mostly from recent reports has been presented for two categories of kefir products: milk used for the production of dairy-based traditional kefir beverages for the lactose-tolerant population, and the plant-sourced substrates used for the production of dairy-free kefir beverages for lactose-intolerant and vegan consumers.

Improvements in the functions of probiotic-based mango pulp rich in phenolic and proline antioxidants by treatment with pectinase and fermentation with lactic acid bacteria

The pulp, juice, and pomace of yellow fruits contain a variety of bioactive compounds. The antioxidant activity was relatively high in pulp, and this part was thus selected for further processing. In Mahachanok mango pulp, pectinase-and-heat treatment significantly increased phenolic content but did not affect carotenoid content and antioxidant capacity. The quality of Mahachanok mango pulp was improved using pectinase and/or heating, and fermentation with lactic acid bacteria (LAB). DPPH and ABTS assays indicated that all LAB strains significantly enhanced phenolic levels (>100%) and antioxidant activity (>300%). Lacticaseibacillus paracasei OR1 could grow effectively in fermented mango pulp, and the cell numbers increased from 6 to 10 log CFU/g. The highest OR1 cell numbers were found in mango pulp after pectinase-and-heat treatment, which released a substrate suitable for OR1 growth. The total phenolic contents and antioxidant activities of all OR1-fermented samples were significantly higher than those of non-fermented mango pulp. OR1 fermentation increased the proline content in mango pulp by 317% in the pectinase-and-heat-treated sample and 200% in the pectinase-treated sample and reduced contamination by yeasts, molds, fecal coliforms, and other bacteria. Therefore, healthy probiotic-based foods rich in phenolic and proline antioxidants could be produced by pectinase-and-heat treatment and LAB fermentation.

From Waste to Taste: Application of Fermented Spent Rootlet Ingredients in a Bread System

The process of upcycling and incorporating food by-products into food systems as functional ingredients has become a central focus of research. Barley rootlets (BR) are a by-product of the malting and brewing industries that can be valorised using lactic acid bacteria fermentation. This research investigates the effects of the inclusion of unfermented (BR-UnF), heat-sterilised (BR-Ster), and five fermented BR ingredients (using Weissella cibaria MG1 (BR-MG1), Leuconostoc citreum TR116 (BR-TR116), Lactiplantibacillus plantarum FST1.7 (BR-FST1.7), Lactobacillus amylovorus FST2.11 (BR-FST2.11), and Limosilactobacillus reuteri R29 (BR-R29) in bread. The antifungal compounds in BR ingredients and the impact of BR on dough rheology, gluten development, and dough mixing properties were analysed. Additionally, their effects on the techno-functional characteristics, in vitro starch digestibility, and sensory quality of bread were determined. BR-UnF showed dough viscoelastic properties and bread quality comparable to the baker's flour (BF). BR-MG1 inclusion ameliorated bread specific volume and reduced crumb hardness. Breads containing BR-TR116 had comparable bread quality to BF, while the inclusion of BR-R29 substantially slowed microbial spoilage. Formulations containing BR-FST2.11 and BR-FST1.7 significantly reduced the amounts of sugar released from breads during a simulated digestion and resulted in a sourdough-like flavour profile. This study highlights how BR fermentation can be tailored to achieve desired bread characteristics.

Symbiotic fermentation study of Acetobacter orientalis and lactic acid bacteria for lactobionic acid enriched yoghurt production

Symbiotic fermentation of lactic acid bacteria and Acetobacter orientalis intended to produce lactobionic acid-enriched yoghurt was studied. Commercial lactic acid bacteria (1%) and A. orientalis (10, 15, 20%) were inoculated in milk and incubated at 30°C for 16 h. Incubation parameters, including acidity, lactose conversion, and bacterial colony count, were analysed every 6th hour. Secondary fermentation parameters like acidification rate, bacterial growth rate, generation time and conversion rate of lactose to lactic acid and lactobionic acid were also estimated. The incubation time and A. orientalis level had significant (P < 0.05) effects on the incubation parameters of the lactobionic acid-enriched yoghurt during the incubation period. This study suggests 20% A. orientalis, 1% lactic bacteria inoculation and 30°C/16 h incubation for yoghurt with higher lactobionic acid content.

Revalorization by lactic acid bacterial fermentation of goat whey from cheese industry as a potential antifungal agent

The industry is continuously searching for new methods to reduce the use of chemical preservatives while still produce safer foods for the consumer. Goat whey is a waste from the cheese industry which is primarily treated as a residue. It is rich in different nutrients and has the potential to be used as a matrix for lactic acid bacteria fermentation. This work aims to find a revalorization of whey for the production of a natural origin antifungal agent by a fermentation that can be used as food ingredient. First different whey culture mediums were developed and fermented. Quantification of different antifungal molecules in whey culture mediums in comparation to a fermentation of De Man, Rogosa and Sharpe (MRS) culture medium evidenced that the production of this antifungal metabolites was similar. The in vitro qualitative and quantitative assays evidenced that the whey-based mediums increased the antifungal activity of the CFS in comparation to the MRS. The fermented whey produced bigger inhibition halos (above 1 cm) in the agar diffusion test in comparation to the fermented MRS (bellow 0.6 cm). Alike, in the minimal fungicidal concentration test the lowest antifungal concentrations were detected on the fermented whey mediums, averaging antifungal concentrations lower than 130 g/L. Finally, a multivariable data analysis determined that more antifungal metabolites yet to be detected were affecting in the antifungal activity from the whey samples. The fermented whey has the potential to be a tool in reducing the use of chemical preservatives in foods.

The effect of different pretreatment methods on jujube juice and lactic acid bacteria-fermented jujube juice

To obtain optimal juice-making methods, three pretreatment methods were selected to evaluate their effects on the quality characteristics of jujube juices before and after lactic acid bacteria fermentation. As a result, significant differences between all detected indicators were observed in fermented and unfermented jujube juices following different pretreatment methods. Jujube juices pretreated with hot water soaking (HS) had better color and higher levels of total sugar, reducing sugar and free amino acids than those pretreated with boiling water steeping (BS) and steam steaming (SS). Remarkably, similar tendencies were also found in the corresponding fermented jujube juices. In contrast, higher levels of total acids were found in all-jujube juices pretreated with BS. After lactic acid bacteria fermentation, however, all of the fermented jujube juices pretreated by the HS method displayed the highest total acid levels. As the major volatile components, the total levels of acids in the HS treatment were also significantly higher than those in the other two pretreatments. Sensory evaluation revealed that the fermented jujube juices after BS treatments showed relatively high acceptability among the panelists. These findings demonstrated valuable direction in improving the product quality of fermented jujube juice.

Improvement in bioconversion efficiency and reduction of ammonia emission by introduction of fruit fermentation broth in a black soldier fly larvae and kitchen waste conversion system.

The black soldier fly (BSF), Hermetia illucens (Diptera: Stratiomyidae), is an insect commonly used for the bioconversion of various organic wastes. Not only can the BSF convert organic waste into macromolecular organic substances, such as insect proteins, but it can also lessen the pollution associated with these waste products by reducing ammonia emissions, for example. In this study, we measured the effects of adding fruit fermentation broth (Fer) and commercial lactic acid bacteria fermentation broth (Em) to kitchen waste (KW), as deodorizing auxiliary substances, on the growth performance of black soldier fly larvae (BSFL), the intestinal flora structure of BSFL, the ammonia emission from the KW substrate, and the microbial community structure of the KW substrate. We found that the addition of Fer or Em increased the body weight of BSFL after 6d of culture, increasing the growth rate by 9.96% and 7.96%, respectively. The addition of Fer not only reduced the pH of the KW substrate but also increased the relative abundance of probiotics, such as Lactobacillus, Lysinibacillus, and Vagococcus, which inhibited the growth of ammonifiers such as Bacillus, Oligella, Paenalcaligenes, Paenibacillus, Pseudogracilibacillus, and Pseudomonas, resulting in the reduction of ammonia emission in the KW substrate. Moreover, the addition of Fer or Em significantly increased the relative abundances of Bacteroides, Campylobacter, Dysgonomonas, Enterococcus, and Ignatzschineria in the gut of BSFL and increased the species diversity and richness in the KW substrate. Our findings provide a novel way to improve the conversion rate of organic waste and reduce the environmental pollution caused by BSF.

Low-intensity ultrasound combines synergistically with Lacticaseibacillus paracasei fermentation to enhance chitin extraction from crab shells

The large amounts of chitin in crab shells can be extracted for use in food and biomedical industries. But the traditional chemical-based chitin extraction uses large amounts of acid and alkali, which are environmentally harmful. The current study explored lactic acid bacteria (Lacticaseibacillus paracasei) fermentation and low-intensity ultrasound combination for crab shells chitin extraction. Our results show that intermittent low-intensity ultrasound (0.167 W/cm2) treatment for 10 min at 8 h intervals enhances bacteria growth to improve decalcification by 16.72% and deproteinization by 33.45% and shortens the fermentation time of crab shells to 48 h. Scanning electron microscopy examination of the fermented chitin revealed that the decalcification and deproteinization were more efficient with this combined treatment, whereas nuclear magnetic resonance and infrared spectroscopy analyses show that the extracted chitin had alpha conformation. Collectively, low-intensity ultrasound could be leveraged together with L. paracasei fermentation to enhance chitin extraction from crab shells.

Effects of lactic acid bacteria fermentation on the physicochemical and structural characteristics of starch in blends of glutinous and japonica rice.

In this study, the effects of lactic acid bacteria (LAB) fermentation on the physicochemical and structural characteristics of mixed starches in blends of glutinous and japonica rice were investigated. Five starter cultures improved in varying degrees the hydration ability, transparency, and freeze-thaw stability of the mixed starches. Mixed starch I, prepared by fermentation of Lactobacillus acidophilus HSP001, exhibited optimal water-holding capacity, solubility, and swelling power. In comparison, mixed starches V and III involved fermentation of L. acidophilus HSP001 and Latilactobacillus sakei HSP002, using ratios of 2:1 and 1:1 to achieve higher transparency and freeze-thaw stability, respectively. The LAB-fermented, mixed starches exhibited excellent pasting properties due to their high peak viscosities and low setback values. Moreover, the viscoelasticity of mixed starches III-V, prepared by compound fermentation of L. acidophilus HSP001 and L. sakei HSP002 in ratios of 1:1, 1:2, and 2:1, respectively, proved superior to their single strain fermentation counterparts. Meanwhile, LAB fermentation resulted in reduced gelatinization enthalpy, relative crystallinity, and short-range ordered degree. Thus, the effects of five LAB starter cultures on mixed starches were inconsistent, but these results provide a theoretical basis for the application of mixed starches. PRACTICAL APPLICATION: Lactic acid bacteria was used to ferment blends of glutinous and japonica rice. Fermented mixed starch had better hydration, transparency, and freeze-thaw stability. Fermented mixed starch exhibited nice pasting properties and viscoelasticity. LAB fermentation corroded starch granules, leading to the decrease of ΔH. Relative crystallinity and short-range order of fermented mixed starch decreased.

Functional Characteristics of Whey Protein-Derived Peptides Produced Using Lactic Acid Bacteria Hydrolysis

Hydrolysis of whey-derived proteins using lactic acid bacteria (LAB) utilizes the mass culture method and fermentation of LAB to produce effective bioactive peptides. Whey protein has the biological potential of its precursors, but the active fragments may not be released depending on the hydrolysis method. As an alternative to these problems, the nutritional and bioactive functionality of the hydrolysis method have been reported to be improved using LAB for whey protein. Peptide fractions were obtained using a sample fast protein liquid chromatography device. Antioxidant activity was verified for each of the five fractions obtained. In vitro cell experiments showed no cytotoxicity and inhibited nitric oxide production. Cytokine (IL [interleukin]-1α, IL-6, tumor necrosis factor-α) production was significantly lower than that of lipopolysaccharides (+). As a result of checking the amino acid content ratio of the fractions selected through the AccQ-Tag system, 17 types of amino acids were identified, and the content of isoleucine, an essential amino acid, was the highest. These properties show their applicability for the production of functional products utilizing dietary supplements and milk. It can be presented as an efficient method in terms of product functionality in the production of uniform-quality whey-derived peptides.

Optimization of strains for fermentation of kiwifruit juice and effects of mono- and mixed culture fermentation on its sensory and aroma profiles

In this study, a quality evaluation model of fermented kiwifruit juice (KJ) based on strain growth characteristics, sensory quality and functional characteristics was established by PCA, and the effects of mono- and mixed culture fermentation on the sensory and aroma profiles of KJ were comparatively studied. Experiments determined that L. brevis (LB) was the optimal strain for monoculture fermentation, and L. plantarum (LP2):LB = 1:2 was the optimum ratio for mixed fermentation. The results showed that lactic acid bacteria (LAB) fermentation significantly reduced the pH, soluble solid content and lightness, and improved its functional characteristics and viscosity. Mixed culture fermentation was superior to monoculture fermentation in terms of colony counts, sensory quality and viscosity. In general, after LAB fermentation, the concentrations of esters, ketones, alcohols and terpenoids in KJ increased significantly, while the concentrations of aldehydes decreased significantly. The production of esters and terpenoids was more strongly promoted by monoculture fermentation, while mixed culture fermentation promoted the production of more ketones and alcohols. 2,5-octanedione and 1-octen-3-ol could be the characteristic aroma compounds of mixed fermented KJ.