Effect Of Lactic Acid Fermentation Research Articles

Transformative effects of lactic acid fermentation on maize and quality protein maize: Phytochemical characterization, functional properties, and structural features

AbstractBackground and ObjectiveFermentation has a huge potential to improve the nutritional and functional properties by using the biological activity of the grain itself. The current study was performed to optimize the conditions for the fermentation of Quality Protein Maize (QPM) and maize further; the impact of fermentation treatment on the bio‐techno‐functional properties of QPM and maize flour was assessed.FindingsThe technological properties, including oil absorption capacity, water solubility index, emulsion activity and stability, foaming capacity and stability, protein solubility, gel consistency, and least gelation concentration, were found to be increased with the fermentation treatment, while water absorption capacity, paste clarity, and swelling power observed a decline. The findings suggested elevated levels of all the bioactive constituents with the fermentation process. The modulations at the molecular level were confirmed by the scanning electron micrographs of fermented flour. Further, changes in the peaks of Fourier transform infrared spectra and the emergence of new peaks were also reported.ConclusionsThe fermentation treatment altered the techno‐functional properties, bioactive constituents, macromolecular structure, and molecular interactions of QPM and maize flour.Significance and NoveltyLimited literature is available dedicated to the assessment of the nutritional, techno‐functional, and phytochemical components in QPM and maize as influenced by the fermentation process. Further, changes in the structural and molecular interactions in the flour components due to fermentation treatment have not been studied comprehensively.

The effect of lactic acid fermentation on the phytochemical content of fig leaf extracts compared to single solvent and sequential solvents extraction

The aim of this study was to compare the antioxidant, natural products, and polyphenolic profiles of Ficus carica L. leaf extracts obtained with a sequential solvent extraction (n-hexane, dichloromethane, ethyl acetate, and methanol), a single solvent extraction with one of three different solvents (methanol, ethanol and ethyl acetate), and a fermentation assisted extraction. Extracts were assessed by high-performance thin-layer chromatography (HPTLC) fingerprinting pattern (before and after derivatization with DPPH free radical, anisaldehyde-sulfuric acid reagent and ferric chloride) and with ATR-FTIR phytochemical profiling. The results show that sequential solvents extraction may maximise the extraction of natural products, especially polyphenolics. However, the highest antioxidant activity was achieved with a single solvent extraction with ethyl acetate. Furthermore, fermentation assisted extraction further improves extraction of antioxidants when compared to single extraction from nonfermented material. In conclusion, brining and spontaneous lactic acid fermentation of plant material is a highly desirable method for improving the functional properties of extracts due to its low cost and low energy requirements.

The Comparative Effect of Lactic Acid Fermentation and Germination on the Levels of Neurotoxin, Anti-Nutrients, and Nutritional Attributes of Sweet Blue Pea (Lathyrus sativus L.).

Grass pea (Lathyrus sativus L.), an indigenous legume of the subcontinental region, is a promising source of protein and other nutrients of health significance. Contrarily, a high amount of β-N-oxalyl-l-α,β-diaminopropionic acid (β-ODAP) and other anti-nutrients limits its wider acceptability as healthier substitute to protein of animal and plant origin. This study was aimed at investigating the effect of different processing techniques, viz. soaking, boiling, germination, and fermentation, to improve the nutrient-delivering potential of grass pea lentil and to mitigate its anti-nutrient and toxicant burden. The results presented the significant (p < 0.05) effect of germination on increasing the protein and fiber content of L. sativus from 22.6 to 30.7% and 15.1 to 19.4%, respectively. Likewise, germination reduced the total carbohydrate content of the grass pea from 59.1 to 46%. The highest rate of reduction in phytic acid (91%) and β-ODAP (37%) were observed in germinated grass pea powder, whereas fermentation anticipated an 89% reduction in tannin content. The lactic acid fermentation of grass pea increased the concentration of calcium, iron, and zinc from 4020 to 5100 mg/100 g, 3.97 to 4.35 mg/100 g, and 3.52 to 4.97 mg/100 g, respectively. The results suggest that fermentation and germination significantly (p < 0.05) improve the concentration of essential amino acids including threonine, leucine, histidine, tryptophan, and lysine in L. sativus powder. This study proposes lactic acid fermentation and germination as safer techniques to improve the nutrient-delivering potential of L. sativus and suggests processed powders of the legume as a cost-effective alternative to existing plant proteins.

Effect of lactic acid fermentation on the quality and phytochemical constituent in smoothies made from the leaves of different sweet potato (Ipomoea batatas L.) cultivars

SummaryThis study investigated the effect of fermentation by Lactiplantibacillus plantarum 75 (L75) on the physicochemical properties, survival of L75, sensory, antioxidants and their activities in leaf smoothies of six sweet potato cultivars [Orange‐fleshed (OFSP): ‘Bophelo’, and ‘Beauregard’; cream‐fleshed (CFSP): ‘Blesbok’ and ‘Ndou’; and purple‐fleshed (PFSP): ‘08.21p’ and ‘Purple‐purple’]. Fermentation significantly affected the physiochemical properties. Fermentation for 24 h improved the carotenoid (TCC), ascorbic acid (AA) (6.8, 6.0 mg 100 g−1) and total phenolic (4435 mg 100 g−1) significantly in, ‘Bophelo’ smoothies. Whilst 48 h fermentation significantly increased the TCC, AA, organic acids, valine and alanine levels in ‘Blesbok’ smoothies'. Principal component analysis separated the unfermented ‘Bophelo’ and Purple‐purple’ leaf smoothies from fermented leaf smoothies of OFSP, CSFP, and PFSP. DPPH scavenging activity and alpha‐carotene were effective markers for separating fermented from unfermented leaf smoothies in the variable importance study. Survival of L75 was influenced by fermentation duration and cultivar type. Fermented and unfermented smoothies were equally acceptable.

Synergistic use of fermentation and extrusion processing to design plant protein-based sausages

The synergistic effect of lactic acid fermentation and high-moisture extrusion processing of pea protein on the microbiological and sensory properties of plant-based sausages was investigated. Plant-based sausages were formed by combining fermented pea protein concentrate (PPC) biomass with high-moisture extruded pea protein isolate (PPI). Pea protein concentrate (PPC) was fermented with Lactococcus lactis subsp. lactis and Lactiplantibacillus plantarum to improve the perceived structure, texture, and flavour (specifically via expression of glutamic acid which is connected to umami flavour) of plant-based sausages.The sausages were prepared by stuffing the mixture of extruded PPI and fermented PPC (addition level 70:30) inside vegetarian casings followed by steam cooking. After preparation and cooking of the sausages, a trained sensory panel evaluated the intensities of ten selected attributes defining the flavour, odour, colour, and texture. In addition, dry matter content, acidification, microbial quality, and glutamate contents were analysed.The results demonstrated that fermentation decreased the pea-like odour and improved the texture of the sausages. In addition, yeast-like odour and umami taste were observed. The study was able to demonstrate novel clean-label processing approaches by combined fermentation and extrusion to generate in-situ meat-like flavour and texture based on plant protein ingredients.

Effect of lactic acid fermentation of red beetroot juice on volatile compounds profile and content

The study aimed to evaluate the effect of lactic acid fermentation on the profile and content of volatile organic compounds (VOCs) in red beetroot juice. Red beetroot juice was fermented by three different amounts (1%, 2%, and 2.5%) of three various Lactobacillus strains (L. acidophilus ATCC 8014, L. brevis Lbbr 12A, L. plantarum ATCC 3543) for 24 h. The head-space micro-extraction (HS-SPME) with gas chromatography–mass spectrometry (GC–MS) was implemented to qualify and quantify the VOCs presence in samples: fresh juice, two controls incubated at 30 and 37 °C, and nine fermented juice samples. A total number of 100 volatiles were identified in the analyzed juice samples, which were classified into 18 chemical groups. Fermented juice samples were characterized by a greater variety of VOCs than unfermented juice samples. In fermented juice samples, 17 to 38 compounds were identified, while in unfermented juice samples, it was 13–15 compounds. The highest number of VOCs was found in juice fermented by L. plantarum (33–38 volatiles) and the lowest in fresh juice (13 volatiles). Total relative content of VOCs ranged from 84.00 (fresh juice) to 881.31 µg/mL (control, 30 °C). On the other hand, the highest relative content of VOCs among fermented juice samples was noticed in the juice fermented by a 1% addition of L. plantarum. According to this study, it can be said that 24-h lactic acid fermentation of red beet juice allows forming a significant amount of volatilized molecules. Therefore, the relatively high content of volatiles can increase potentially the aroma attractiveness of red beetroot juice.

Insight into the role of lactic acid bacteria in the development of a novel fermented pistachio (Pistacia vera L.) beverage

This study aimed to assess the fermentability of a pistachio-based beverage. The effects of lactic acid fermentation on the odor profile and the stability of the beverage were also assessed. To this end, a procedure for obtaining a pistachio beverage was developed, and the nutritional composition of the beverage was obtained. The beverage was characterized by a high content of fiber (2.9%), fat (4.6%), and protein (2%), and contained high amounts of K and Mg. For the experiment, 43 cultures of the following lactic acid bacteria were used: Companilactibacillus paralimentarius, Companilactibacillus kimchi, Levilactibacillus brevis, Lactiplantibacillu pentosus, Lactiplantibacillus plantarum, Lactiplantibacillus paraplantarum, Latilactobacillus curvatus, Leuconostoc pseudomesenteroides, and Furfurilactobacillus rossiae. The cultures were evaluated for the following technological characteristics: i) growth and acidifying activity, ii) production of exopolysaccharides; iii) presence of histidine decarboxylase (hdcA) gene; iv) antimicrobial activity against Listeria innocua. The cultures were used in model pistachio-based fermentations to assess their ability to grow and acidify. The odor profile of the beverage after 24 h fermentation was assessed using an electronic nose system (E-nose). The pistachio-based beverage resulted an optimal substrate for lactic acid bacteria that reached loads between 8 and 10 log CFU/mL and acidified the beverage to pH values between 4 and 5.5. In the beverage, viable counts of all cultures remained above 8 log CFU/mL after 30 days of storage at 4 °C. The E-nose analysis represented a valid screening method to evaluate the effects of the fermentative activity of microbial starters on the qualitative characteristics of this novel food matrix.

Effect of lactic acid fermentation and in vitro digestion on the bioactive compounds in Chinese wolfberry (Lycium barbarum) pulp

Two commercial probiotics, Lactobacillus helveticus 76 (Lh) and Bifidobacterium lactis 80 (Bla), were employed to investigate the effect of lactic acid fermentation and in vitro digestion on bioactive compounds in Chinese wolfberry pulp. The changes of antioxidant capacity of pulp were also studied. Our results demonstrated that Chinese wolfberry pulp was a suitable carrier for both probiotics. Lactic acid fermentation increased total phenolic, total flavonoids and betaine, and improved bioaccessibility of flavonoids and carotenoids in vitro digestion. Fermentation had no remarkable influence on the content and basic structure of polysaccharides, but reduced their particle size. In addition, fermentation improved the antioxidant activities of Chinese wolfberry pulp before and after in vitro digestion mainly due to the metabolism of polyphenols. This study thus would provide valuable information about the development of Chinese wolfberry as a functional drink fermented with probiotics.

Effect of Lactic Acid Fermentation on Phytochemical Content, Antioxidant Capacity, Sensory Acceptability and Microbial Safety of African Black Nightshade and African Spider Plant Vegetables

Traditional preparation of African indigenous vegetables (AIVs) such as African black nightshade (Solanum nigrum) and African spiderplant (Cleome gynandra) involves either boiling and discarding the first water or lengthy boiling. Fermentation is considered a better alternative processing technique due to the enhanced retention of phytochemical contents and sensory properties. However, little is known about the impact of lactic acid fermentation on the phytochemical content, antioxidant capacity, sensory acceptability and microbial safety of the African black nightshade and African spiderplant. This study aimed to ferment AIVs using combined starter cultures (Lactobacillus fermentum and Lactococcus lactis) and further determine their effect on the phytochemical content (phenolic compounds and flavonoids), antioxidant capacity, sensory acceptability and microbial safety of the vegetables. There was a marked increase in phenol and flavonoid contents in all fermented vegetables (p &lt; 0.05). The highest phenol content was 228.8 mg/g GAE (gallic acid equivalent) in the starter-culture-inoculated African black nightshade, while flavonoid content was 10.6 mg/g QE (quercetin equivalent) in the same. Starter-culture-inoculated AIVs presented significantly higher antioxidant capacity with a 60–80% radical scavenging activity compared to levels in uninoculated batches (p &lt; 0.05). Fermented vegetables were more liked than the boiled vegetables and were microbiologically safe. In conclusion, lactic fermentation of AIVs increased phytochemical contents (phenolic compounds and flavonoids), maintained antioxidant capacity and improved product safety and sensory acceptability. Therefore, fermentation and consumption of the African indigenous vegetables are to be encouraged.

Effect of Lactiplantibacillus plantarum fermentation on the in-vitro antioxidant and angiotensin I-converting enzyme-inhibitory properties of turmeric, coriander, cumin, and red chili pepper suspensions

In this study, we investigated the effects of lactic acid fermentation by the selected strains of Lactiplantibacillus plantarum on the antioxidant and angiotensin I-converting enzyme (ACE)-inhibitory properties of four popular spice suspensions, namely turmeric (Curcuma longa), coriander (Coriandrum sativum), cumin (Cuminum cyminum), and red chili pepper (RCP) (Capsicum annuum). Among these, the RCP suspension exhibited the most significant positive changes following fermentation with L. plantarum Tennozu-SU3, whereby the total phenolic content, antioxidant capacity (2,2-diphenyl-1-picrylhydrazyl and O2− scavenging), and rabbit lung ACE-inhibitory activity were increased. The fermented RCP suspension was then fractionated via ultrafiltration. The 10–30 kDa fraction was speculated as the component that increased antioxidant and ACE-inhibitory activities of RCP. Moreover, although the ACE-inhibitory effect of the RCP suspension on rabbit lung ACE was significantly increased after fermentation (41 folds), this was not observed in murine organs (lungs, kidneys, and testes) or on recombinant human ACE. Our findings suggest that the inhibitory effect of fermented RCP suspension on the rabbit lung ACE was not extended to ACE from other animals, including humans.

The effect of lactic acid fermentation of Bactronophorus thoracites on antimicrobial activity against rice pathogens

The effect of lactic acid fermentation of Bactronophorus thoracites on antimicrobial activity against rice pathogens

The Effect of Lactic Acid Fermentation on Extraction of Phenolics and Flavonoids from Sage Leaves

This work analysed the effect of spontaneous fermentation of sage leaves on the release and extraction of flavonoid and phenolic compounds. Chemical profiling based on thin-layer chromatography was used to compare different extracts from two sage species, common sage (Salvia officinalis) and white sage (Salvia apiana). Non-fermented Salvia apiana extracts are richer in antioxidants, phenolics, and terpenoids. Fermentation significantly enhances extraction of total phenolics, flavonoids, and antioxidants only from Salvia officinalis leaves, while it does not affect extraction from Salvia apiana leaves. In each 20 µL of extract, extraction of polyphenolics increases from 6.55 to 21.01 µg gallic acid equivalents (GAE), anti-oxidants from 0.68 to 2.12 µg GAE, and flavonoid content from 48.01 to 65.33 µg RE (rutin equivalents). Higher antioxidant activity in fermented Salvia apiana ethyl acetate extracts is associated with an increased concentration of phenolics and phenolic terpenoids. However, in Salvia officinalis, the higher antioxidant activity of fermented extract is a result of the release and improved extraction of flavonoids, as there is no increase in the extraction of phenolics. Lactic acid produced via fermentation and proline from Salvia officinalis leaves forms a natural deep eutectic solvent (NADES), which significantly increases the solubility of flavonoids.

Effect of Lactic Acid Fermentation on Legume Protein Properties, a Review

Legume proteins have a promising future in the food industry due to their nutritional, environmental, and economic benefits. However, their application is still limited due to the presence of antinutritional and allergenic compounds, their poor technological properties, and their unpleasant sensory characteristics. Fermentation has been traditionally applied to counteract these inconveniences. At present, lactic acid fermentation of legumes is attracting the attention of researchers and industry in relation to the development of healthier, tasty, and technologically adapted products. Hence, we aimed to review the literature to shed light on the effect of lactic acid fermentation on legume protein composition and on their nutritional, functional, technological, and sensorial properties. The antimicrobial activity of lactic acid bacteria during legume fermentation was also considered. The heterogenicity of raw material composition (flour, concentrate, and isolate), the diversity of lactic acid bacteria (nutriment requirements, metabolic pathways, and enzyme production), and the numerous possible fermenting conditions (temperature, time, oxygen, and additional nutrients) offer an impressive range of possibilities with regard to fermented legume products. Systematic studies are required in order to determine the specific roles of the different factors. The optimal selection of these criteria will allow one to obtain high-quality fermented legume products. Fermentation is an attractive technology for the development of legume-based products that are able to satisfy consumers’ expectations from a nutritional, functional, technological, and sensory point of view.

Effect of lactic acid fermentation on the nutritional quality and consumer acceptability of African nightshade.

African nightshade (ANS) is among many underexploited and neglected indigenous vegetables. This study assessed the effect of lactic acid fermentation (LAF) on nutritional and sensory quality in Solanum villosum (Sv) and Solanum scabrum (Ss). Spontaneously fermented (SF) and controlled fermented (CF) conditions using Lactobacillus plantarum LP90 and Leuconostoc mesenteroides LM58 were employed for 15 days and 120 h. From the fermented pickles, relish products were prepared using cooking oil and a variety of spices. The relish products were subjected to a consumer acceptability test. Results show a significant drop in pH to <3.5, increasing titratable acidity (TTA) to around 0.6 after 120 h and 15 days of CF and SF, respectively. LAF resulted in a 2.6–5 and 1.6–4.8‐fold significant rise in β‐carotene in pickles and their relish products. All pickles and relish products exhibited a significant decrease (p < .05) in vitamin C by 88.33%–95.90%. LAF significantly reduced total phenolic (26%– 43%) and Chlorophyll (16.45%–39.25%). On the other hand, LAF showed improvement in minerals content (P, Ca, Fe, and Zn) and reduction of tannin (76.27%–92.88%) and oxalate (77.33%–90%) levels. LAF relish products were highly preferred by the consumers, with S. villosum controlled fermented relish (SvCFR) leading. All fermented relishes were stable at ambient (27°C) and refrigeration (4°C) temperatures after 6 months of storage. Generally, LAF is an effective method for ANS preservation, with improved nutritional quality and safety. LAF can therefore be recommended to small‐scale farmers, processors, and households for ANS preservation. Ultimately, this method enhances the nutrition and sensory quality, safety, and livelihood.

Influence of Lactic Acid Bacterium Strains on Changes in Quality, Functional Compounds and Volatile Compounds of Mango Juice from Different Cultivars during Fermentation.

The effects of lactic acid fermentation using Lactiplantibacillus plantarum 75 (L75), Leuconostoc pseudomesenteroides 56 (L56) and its combination (L56 + 75) on the quality, bioactive and volatile compounds of mango juices (MJ) from three cultivars (‘Peach’, ‘Sabre’ and ‘Tommy Atkins’) were investigated. Fermented and unfermented MJ were evaluated for LAB growth, physicochemical parameters, volatile compounds, antioxidants activities (DPPH, ABTS, FRAP methods), total phenolic content (TPC) and sensory properties. The unfermented juices served as a control. Twenty-four-hour fermentation was ideal for MJ based on LAB growth profiles. Generally, titratable acidity, TPC, FRAP, DPPH and ABTS scavenging activities significantly increased with fermentation by the L75 strain and were highest in the L75-fermented ‘Sabre’ MJ, while L75-fermented ‘Peach’ MJ had higher ABTS activity (p < 0.05). In contrast, the L56 strain enhanced β-carotene retention, with improved colour properties in L56-fermented ‘Peach’ MJ. Fermentation with L75 in ‘Sabre’ and ‘Peach’ MJ aided the synthesis of new volatile compounds (alcohols, esters, ketones and aldehydes). A PLS-DA scatter plot showed two clusters separating the ‘Peach’ and ‘Sabre’ mango juice fermented with L75 from the rest. Based on the variable importance of the projection value (VIP) scores, pentadecane, 8-hexyl and butyl isobutyrate were shown as marker candidates to distinguish ‘Peach’ and ‘Sabre’ MJ fermented with L75 from the other treatments, whereas ethyl octanoate and isobutyl acetate differentiated the ‘Sabre’ MJ fermented with L75 from the other treatments. ‘Sabre’ and ‘Peach’ MJ fermented with L75 and L56 could provide antioxidants, meeting the recommended daily requirements for ascorbic acid and carotenoids in adults and teenagers. Hence, lactic acid fermentation of these local cultivars is a way to benefit consumers.

Effect of Lactic Acid Fermentation on Volatile Compounds and Sensory Characteristics of Mango (Mangifera indica) Juices.

Fermentation is a sustainable bio-preservation technique that can improve the organoleptic quality of fruit juices. Mango juices were fermented by monoculture strains of Lactiplantibacillus plantarum subsp. plantarum (MLP), Lacticaseibacillus rhamnosus (MLR), Lacticaseibacillus casei (MLC), Levilactobacillus brevis (MLB), and Pediococcus pentosaceus (MPP). Volatile compounds were sorbed using headspace solid phase microextraction, separated, and identified with gas chromatography-mass spectrometry. Forty-four (44) volatile compounds were identified. The control, MPP, and MLB had higher amounts of ethyl acetate, ethyl butyrate, 2-hexenal, 2,6-nonadienal, 2,2-dimethylpropanal, β-selinene, γ-gurjunene, α-copaene, and δ-cadinene, while MLC, MLP, and MLR had higher amounts of 2,3-butanedione and a cyclic hydrocarbon derivate. Consumers (n = 80) assessed their overall liking and characterized sensory attributes (appearance, color, aroma, flavor, consistency, acidity, and sweetness) using check-all-that-apply, and penalty analysis (just-about-right). Overall liking was associated with ‘mango color’, ‘pulp’, ‘mango aroma’, ‘sweet’, ‘natural taste’, and ‘mango flavor’ that described the control, MLB, MLC and MPP. Juices MLR and MLP were described as ‘bitter’, ‘sour’, ‘aftertaste’, and ‘off-flavor’. Multivariate analysis revealed relationships between the volatile compounds, mango juices fermented by different lactic acid bacteria, and sensory characteristics. Thus, the type of lactic acid bacteria strains determined the volatile and sensory profile of mango juices.

Phenolics Profile, Antioxidant Activity and Flavor Volatiles of Pear Juice: Influence of Lactic Acid Fermentation Using Three Lactobacillus Strains in Monoculture and Binary Mixture.

The aim of this study was to evaluate the effects of lactic acid fermentation using three Lactobacillus strains (Lactiplantibacillus plantarum 90, Lactobacillus helveticus 76, and Lacticaseibacillus casei 37) in monoculture and binary mixture on phenolics profile, antioxidant activity and flavor volatiles in pear juice. Results showed that the colony counts of binary mixture were higher than monoculture in fermented pear juice. The total content of phenols was increased, while that of flavonoids was decreased significantly during fermentation (p < 0.05). Antioxidant activities in fermented peer juice including DPPH and ABTS radical scavenging abilities and ferric reducing antioxidant power (FRAP) were significantly improved (p < 0.05). Binary mixture of Lactiplantibacillus plantarum 90 and Lacticaseibacillus casei 37 fermentation exhibited strong DPPH radical scavenging ability, due to the increase in vanillic acid and arbutin contents. Furthermore, lactic acid fermentation improved the formation of alcohols, esters, acids and terpenoids, and reduced the contents of aldehydes and ketones. Thirty new compounds including 15 alcohols, seven esters, five acids, and three terpenoids were observed in fermented pear juice. Hierarchical cluster revealed that flavor volatiles in pear juice were improved dramatically by Lactobacillus strains fermentation, and there were dramatic differences between monoculture and binary mixture.

Combined effect of various salt concentrations and lactic acid bacteria fermentation on the survival of Escherichia coli O157:H7 and Listeria monocytogenes in white kimchi at different temperatures.

This study was conducted to investigate the effect of lactic acid fermentation and salt on the survival of Escherichia coli O157:H7 and Listeria monocytogenes in white kimchi containing various salt concentrations during storage at 4 and 15°C. The survivals of pathogens during fermentation differed depending on salt concentrations and storage temperature. The survival of pathogens in kimchi containing 3% salt was higher than that in kimchi containing 1 and 2% salt, which may be related to the fact that lactic acid bacteria remained constant throughout the initial stage of fermentation. Thus, there was a lower reduction in the pH of kimchi containing 3% salt regardless of storage temperature. These protective effects may result from a gradual reduction in pH; however, the mechanisms are not clearly understood. Therefore, further investigations are needed to explain the mechanism by which lactic acid fermentation and salt in kimchi affect the growth of foodborne pathogens.

Effect of lactic acid fermentation of watermelon juice on its sensory acceptability and volatile compounds

Fermentation increases food shelf-life but is characterized by changes that affect product's perception. Watermelon juice was fermented with Lactobacillus plantarum (WJ-LP), L. rhamnosus (WJ-LR), L. casei (WJ-LC), L. brevis (WJ-LB) and Pediococcus pentosaceus (WJ-PP). Their sensory characteristics and volatile compounds were investigated by consumers and Headspace Solid Phase Microextraction integrated with Gas Chromatography-Mass Spectrometry, respectively. WJ-PP and WJ-LB were most liked and perceived with ‘watermelon-flavor’, ‘natural taste’, ‘sweet’ and ‘watermelon-color’ while WJ-LC, WJ-LP and WJ-LR were least liked and perceived as ‘sour’, ‘bitter’, ’off-flavor’, ‘aftertaste’ and ‘intense-flavor’. Fifty-four volatiles were identified. After fermentation, alcohols, ketones, monoterpenes, acids, and furans increased while aldehydes and alkanes decreased. Lactic acid fermentation introduced 4-decanone and 2,3-butanedione in WJ-LB, WJ-LC, WJ-LP and WJ-LR, however, heptanal, 2-heptenal, 2,6-nonadienal, 2-decenal, and 2,4-decadienal in WJ-LC, heptanal, 2-hexenal, 2-heptenal, 2,6-nonadienal, 2-decenal and octanal in WJ-LR and 2,6-dimethyl-2,6-octadiene in WJ-LP disappeared. Juice sensory profiles were associated with their volatile compounds.

The effect of lactic acid fermentation with different bacterial strains on the chemical composition, immunoreactive properties, and sensory quality of sweet buttermilk

This paper describes the successful development of new low-immunoreactive buttermilk (BM)-based formulations which were fermented with 31 lactic acid bacteria (LAB) and Bifidobacterium strains. The aim of this study was to create a new formula, which can serve as potential candidates for the immunotherapy of allergy. Preparations were tested for their content of biologically active compounds, such as proteins, peptides, phospholipids, and short-chain fatty acids (SCFA), as well as for the survivability of LAB and sensory quality. The results showed that the BM was a matrix rich in nutritional components and displayed higher than expected susceptibility to the reduction of protein IgE-immunoreactivity (to 98%) and high bacterial-protecting capacity. The overall sensory quality of examined products was influenced by the profile of SCFA and free peptides, but two formulations fermented with Lactobacillus delbrueckii ssp. bulgaricus-151 and Lactobacillus casei-LcY were the most advantageous with desirable sensory, immunoreactive, and biochemical properties.