Identification of antioxidant peptides from cheddar cheese made with Lactobacillus helveticus

Implementation of plant extracts for cheddar-type cheese production in conjunction with FTIR and Raman spectroscopy comparison

Plant extracts have demonstrated the ability to act as coagulants for milk coagulation at an adequate concentration, wide temperatures and pH ranges. This research is focused on the use of different vegetative extracts such as Citrus aurnatium flower extract (CAFE), bromelain, fig latex, and melon extract as economical and beneficial coagulants in the development of plant-based cheddar-type cheese. The cheddar-type cheese samples were subjected to physicochemical analysis in comparison to controlled cheese samples made from acetic acid and rennet. The fat, moisture, protein, and salt contents remained the same over the storage period, but a slight decline was observed in pH. The Ferric reducing antioxidant power (FRAP) increased with the passage of the ripening period. The FTIR and Raman spectra showed exponential changes and qualitative estimates in the binding and vibrational structure of lipids and protein in plant-based cheeses. The higher FTIR and Raman spectra bands were observed in acid, rennet, bromelain, and CAFE due to their firm and strong texture of cheese while lower spectra were observed in cheese made from melon extract due to weak curdling and textural properties. These plant extracts are economical and easily available alternative sources for cheese production with higher protein and nutritional contents.

Influence of sonication pretreatment on antiradical and anti-ACE activity of protein hydrolysates from fermented pork loins

The aim of this study was to assess whether ultrasound treatment (sonification time: 5, 15, and 30 min; constants: ∼40 kHz, ∼2.5 W cm2) can be applied prior to hydrolysis to enhance the anti-radical and angiotensin converting enzyme inhibiting (anti-ACE) effect of the hydrolysates from fermented pork loins. Enzymatic hydrolysis was performed using pepsin, followed by pancreatin. The influence of meat matrix on the course of hydrolysis, shaped using a lactic acid bacteria (LAB)-based starter culture, was also analyzed. It was found that proteases caused a systematic increase in the content of peptides, while pancreatin limited the peptide content in the protein hydrolysate from the loins subjected to spontaneous fermentation. Moreover, for these tests, sonication time had a negligible effect on the peptides content of the hydrolysates. On the other hand, for the sample of LAB-fermented products, both sonication time and stage of hydrolysis promoted the biological activity of the hydrolysates. Samples from the LAB-fermented meat had more peptides at the stage of digestion with pepsin and pancreatin, exhibiting much faster antiradical and anti-ACE activity compared to the control sample. The obtained results suggest that the use of LAB promotes the release of antiradical peptides during the two-step enzymatic hydrolysis, the duration of which can be shortened to achieve satisfactory biofunctionalities. Additional application of sonication pretreatment allows controlling the course of the hydrolysis, as the pro-health, biological effect of some protein-derived sequences is associated with the content of peptides.

Determination of the effects of proteolysis-based changes by adjunct lactobacilli on the bioactivity (ACE-inhibitory and antioxidant activities) of cheese: a model cheese study

Bioactive properties, proteolysis and microbiology of model cheeses with and without adjunct lactobacilli (Lactobacillus helveticus, Lactiplantibacillus plantarum, Lactobacillus bulgaricus and L. casei) were studied during 120 days of storage at 8 or 16 °C. Bioactive properties were observed in peptide fractions (< 3 kDa, 3-10 kDa, < 10 kDa) separated using ultrafiltration membranes. Antioxidant activity of these fractions was determined by radical scavenging assays as ABTS [2, 2'-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid)]. Angiotensin-converting enzyme-inhibitory (ACE-i) activity (% and IC50) and peptide profiles of 70% ethanol-soluble and -insoluble fractions were determined by RP-HPLC. Use of lactobacilli as an adjunct culture significantly changed the RP-HPLC peptide profiles of the cheeses; however, slight changes were observed in the patterns of urea-polyacrylamide gel electrophoresis. Fractions smaller than 3 kDa had higher ACE-i and antioxidant activities for all cheese samples. In conclusion, this study indicates that the addition of lactobacilli as an adjunct culture contributed to the formation of bioactive compounds in the model cheeses and also changed the proteolysis levels.

Fabrication of UF-white cheese: Obtaining a different proteolysis rate, texture, and flavor via using combinations of mesophilic starter culture and Lactobacillus helveticus

The effect of using mesophilic starter culture (Lactococcus lactis ssp. lactis and Lactococcus lactis ssp. cremoris) and Lactobacillus helveticus (L. helveticus) at different ratios (100:0, 75:25, 50:50, 25:75, and 0:100) on the quality properties of UF-white cheese during 90 days of ripening was studied. The results revealed that an increase in L. helveticus ratio caused a significant decrease in the pH and total protein contents of the cheeses (p < .05). No significant changes were observed in the dry matter content of the cheeses (p > .05). The use of higher ratios of L. helveticus led to a noticeable increase in proteolysis and lipolysis indices in the cheeses (p < .05). The cheese produced with higher ratios of L. helveticus had less storage (G') and loss (G″) moduli compared to other cheeses. The more open structure was seen in the cheeses produced using higher ratios of L. helveticus. Regarding sensory properties, lower scores of body and texture, and higher scores of odor and flavor were assigned to the cheeses produced using higher ratios of L. helveticus. In conclusion, the use of combinations of mesophilic starter culture and L. helveticus at specific ratios (75:25 and 25:75) led to improve quality characteristics of UF-white cheese.

Unlocking Flavor Potential Using Microbial β-Glucosidases in Food Processing

Aroma is among of the most important criteria that indicate the quality of food and beverage products. Aroma compounds can be found as free molecules or glycosides. Notably, a significant portion of aroma precursors accumulates in numerous food products as nonvolatile and flavorless glycoconjugates, termed glycosidic aroma precursors. When subjected to enzymatic hydrolysis, these seemingly inert, nonvolatile glycosides undergo transformation into fragrant volatiles or volatiles that can generate odor-active compounds during food processing. In this context, microbial β-glucosidases play a pivotal role in enhancing or compromising the development of flavors during food and beverage processing. β-glucosidases derived from bacteria and yeast can be utilized to modulate the concentration of particular aroma and taste compounds, such as bitterness, which can be decreased through hydrolysis by glycosidases. Furthermore, oral microbiota can influence flavor perception by releasing volatile compounds that can enhance or alter the perception of food products. In this review, considering the glycosidic flavor precursors present in diverse food and beverage products, we underscore the significance of glycosidases with various origins. Subsequently, we delve into emerging insights regarding the release of aroma within the human oral cavity due to the activity of oral microbial glycosidases.

From microbes to molecules: a review of microbial-driven antioxidant peptide generation

Oxidative stress, arising from excess reactive oxygen species (ROS) or insufficient antioxidant defenses, can damage cellular components, such as lipids, proteins, and nucleic acids, resulting in cellular dysfunction. The relationship between oxidative stress and various health disorders has prompted investigations into potent antioxidants that counteract ROS's detrimental impacts. In this context, antioxidant peptides, composed of two to twenty amino acids, have emerged as a unique group of antioxidants and have found applications in food, nutraceuticals, and pharmaceuticals. Antioxidant peptides are sourced from natural ingredients, mainly proteins derived from foods like milk, eggs, meat, fish, and plants. These peptides can be freed from their precursor proteins through enzymatic hydrolysis, fermentation, or gastrointestinal digestion. Previously published studies focused on the origin and production methods of antioxidant peptides, describing their structure-activity relationship and the mechanisms of food-derived antioxidant peptides. Yet, the role of microorganisms hasn't been sufficiently explored, even though the production of antioxidant peptides frequently employs a variety of microorganisms, such as bacteria, fungi, and yeasts, which are recognized for producing specific proteases. This review aims to provide a comprehensive overview of microorganisms and their proteases participating in enzymatic hydrolysis and microbial fermentation to produce antioxidant peptides. This review also covers endogenous peptides originating from microorganisms. The information obtained from this review might guide the discovery of novel organisms adept at generating antioxidant peptides.

The Peptide Fractions of Cheddar Cheese Made with Lactobacillus helveticus 1.0612 Play Protective Effects in H2O2-Induced Oxidative-Damaged Caco-2 Cells Models

In this study, water-soluble peptide (WSP) fractions of cheddar cheese made with Lactobacillus helveticus 1.0612 were purified into WSP-Ⅰ (<3 kDa), WSP-Ⅱ (3-10 kDa), and WSP-Ⅲ (>10 kDa). The protective effects of WSP, WSP-Ⅰ, WSP-Ⅱ, and WSP-Ⅲ fractions against oxidative stress in Caco-2 cells were assayed, and the cytoprotective mechanism of WSP-Ⅰ on cells oxidative damage was elucidated via metabolomics. The results showed that all four peptide fractions were able to attenuate the decrease in cell viability caused by oxidative stress and also could reduce the production of reactive oxygen species and malondialdehyde caused by oxidative stress, and increased cellular catalase and superoxide dismutase activities, thereby enhancing cellular antioxidant capacity. The WSP-Ⅰ fraction with the highest protective effect was used for metabolomics analysis, and 15 significantly different metabolites were screened. Functional pathway analysis revealed that the protective effect of the WSP-I fraction was related with nine metabolic pathways and weakened the metabolic disorders caused by H₂O₂ via regulating energy metabolism and amino acid metabolism. All in all, peptide fractions of cheddar cheese showed a cytoprotective effect through improved cellular metabolism.

Comparative Peptidomics Analysis of Milk Fermented by Lactobacillus helveticus

Lactobacillus helveticus is one of the commonly used starter cultures for manufacturing various fermented dairy products. However, only a few studies have explored the cleavage region preference of L. helveticus with different cell envelope proteinase (CEP) genes. In the present study, we profiled the peptide composition of milk samples fermented by three different L. helveticus strains by means of peptidomics to illustrate their different proteolysis patterns. The result revealed that the differences in peptide profiles of milk samples fermented by different L. helveticus strains were mainly a result of variations in the peptide patterns of the casein fractions, which were correlated with CEP genotypes. This was mainly reflected in the extensiveness of the hydrolysis region of αS1-casein and the degree of β-casein hydrolysis. Bioactive peptides were mostly derived from the hydrolysis region common to the three L. helveticus strains, and DQHXN-Q32M42 fermentation resulted in the highest diversity and abundance of bioactive peptides and a significant antihypertensive effect in spontaneous hypertension rats.

Characterization, High-Density Fermentation, and the Production of a Directed Vat Set Starter of Lactobacilli Used in the Food Industry: A Review

Lactobacilli have been widely concerned for decades. Bacteria of the genus Lactobacillus have been commonly employed in fermented food to improve the appearance, smell, and taste of food or prolong its shelf-life. They comprise 261 species (by March 2020) that are highly diverse at the phenotypic, ecological, and genotypic levels. Some Lactobacilli strains have been documented to be essential probiotics, which are defined as a group of living microorganisms that are beneficial to the health of the host when ingested in sufficiency. However, the characterization, high-density fermentation, and the production of a directed vat set (DVS) starter of Lactobacilli strains used in the food industry have not been systematically reported. This paper mainly focuses on reviewing Lactobacilli as functional starter cultures in the food industry, including different molecular techniques for identification at the species and strain levels, methods for evaluating Lactobacilli properties, enhancing their performance and improving the cell density of Lactobacilli, and the production techniques of DVS starter of Lactobacilli strains. Moreover, this review further discussed the existing problems and future development prospects of Lactobacilli in the food industry. The viability and stability of Lactobacilli in the food industry and gastrointestinal environment are critical challenges at the industrial scale. The new production equipment and technology of DVS starter of Lactobacilli strains will have the potential for large-scale application, for example, developing low-temperature spray drying, freezing granulation drying, and spray freeze-drying.

Selection of Potential Probiotic Yeasts from Dry-Cured Xuanwei Ham and Identification of Yeast-Derived Antioxidant Peptides

The aim of this study was to select potential probiotic yeasts from dry-cured Xuanwei ham and investigate yeast-derived antioxidant peptides. The results showed that two strains (XHY69 and XHY79) were selected as potential probiotic yeasts and identified as Yamadazyma triangularis. The two yeasts showed tolerance under pH 2.5 and 1% bile salt, in addition to protease activity, auto-aggregation, antibacterial, and antioxidant activities. The peptide fraction (MW < 3 kDa) isolated from XHY69 fermentation broth, named XHY69AP, showed higher radical scavenging activities than glutathione at a concentration of 4.5 mg/mL (p < 0.05). The fraction (AP-D10) was purified from XHY69AP by gel filtration chromatography and reversed-phase high performance liquid chromatography, and then further identified by a UHPLC-LTQ-Orbitrap mass spectrometer. The molecular weight of all 55 purified sequences was distributed between 0.370 and 0.735 kDa. Among these seven novel peptides, Tyr-Pro-Leu-Pro (YPLP), Ala-Gly-Pro-Leu (AGPL), Gly-Pro-Phe-Pro (GPFP), and Ala-Pro-Gly-Gly-Phe (APGGF) were identified. All sequences were abundant in hydrophobic amino acids, especially proline residue. Among these novel peptides, YPLP possessed the highest ABTS scavenging rate (75.48%). The present work selects two new probiotic potential yeasts from dry-cured Xuanwei ham that are effective to yield novel antioxidant peptides.

Effect of In Vitro Digestion on the Antioxidant and Angiotensin-Converting Enzyme Inhibitory Potential of Buffalo Milk Processed Cheddar Cheese

The purpose of this study was to develop an in-vitro digestion protocol to evaluate the antioxidant potential of the peptides found in processed cheddar cheese using digestion enzymes. We first studied antioxidant and angiotensin-converting enzyme (ACE) inhibition and antioxidant activities of processed cheddar cheese with the addition of spices e.g., cumin, clove, and black pepper made from buffalo milk and ripened for 9 months. Then we conducted an in vitro digestion of processed cheddar cheese by gastric and duodenal enzymes. Freeze-dried water (WSE) and ethanol-soluble fractions (ESE) of processed cheddar cheese were also monitored for their ACE inhibition activity and antioxidant activities. In our preliminary experiments, different levels of spices (cumin, clove, and black pepper) were tested into a cheese matrix and only one level 0.2 g/100 g (0.2%) based on cheese weight was considered good after sensory evaluation. Findings of the present study revealed that ACE-inhibitory potential was the highest in processed cheese made from buffalo milk with the addition of 0.2% cumin, clove, and black pepper. A significant increase in ACE-inhibition (%) of processed cheddar cheese, as well as its WSE and ESE, was obtained. Lower IC₅₀ values were found after duodenal phase digestion compared to oral phase digestion.

A Review on Health-Promoting, Biological, and Functional Aspects of Bioactive Peptides in Food Applications

Food-derived bioactive peptides are being used as important functional ingredients for health-promoting foods and nutraceuticals in recent times in order to prevent and manage several diseases thanks to their biological activities. Bioactive peptides are specific protein fractions, which show broad applications in cosmetics, food additives, nutraceuticals, and pharmaceuticals as antimicrobial, antioxidant, antithrombotic, and angiotensin-I-converting enzyme (ACE)-inhibitory ingredients. These peptides can preserve consumer health by retarding chronic diseases owing to modulation or improvement of the physiological functions of human body. They can also affect functional characteristics of different foods such as dairy products, fermented beverages, and plant and marine proteins. This manuscript reviews different aspects of bioactive peptides concerning their biological (antihypertensive, antioxidative, antiobesity, and hypocholesterolemic) and functional (water holding capacity, solubility, emulsifying, and foaming) properties. Moreover, the properties of several bioactive peptides extracted from different foods as potential ingredients to formulate health promoting foods are described. Thus, multifunctional properties of bioactive peptides provide the possibility to formulate or develop novel healthy food products.