Milk and Dairy Products as Functional Foods: A Review

Common foods for boosting human immunity: A review

We are frequently exposed to potentially harmful microbes of various types on a daily basis. Our immune system is an amazing collection of unique organs and cells that defends us from hazardous germs as well as certain diseases. It plays a crucial role in protecting the body against external invaders, including bacteria, viruses, and parasites. Maintaining a healthy immune system requires consuming a balanced diet that provides a variety of macro- and micronutrients. By consuming sufficient amounts of water, minerals such as zinc and magnesium, micronutrients, herbs, and foods rich in vitamins C, D, and E, and adopting a healthy lifestyle, one can enhance their health and immunity, and prevent infections. This article provides a comprehensive review of the scientific literature on common foods known for their potential to boost human immunity. The review begins by discussing the various components of the immune system and their functions. It then delves into the current understanding of how nutrition can influence immune response, highlighting the importance of a well-balanced diet in supporting optimal immune function. The article presents an extensive analysis of a range of common foods that have been studied for their immune-boosting properties. These foods include fruits, vegetables, whole grains, and animal-based foods. Each food category is explored in terms of its specific nutrients and bioactive compounds that contribute to immune support. Foods such as milk, eggs, fruits, leafy greens, and spices like onion, garlic, and turmeric contain beneficial compounds that can enhance the immune system's function, activate and inhibit immune cells, and interfere with multiple pathways that eventually lead to improved immune responses and defense. The available literature on the issue was accessed via online resources and evaluated thoroughly as a methodology for preparing this manuscript.

Antioxidant and antihypertensive activity of Gouda cheese at different stages of ripening

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More intense proteolysis at 90 days caused an increase in antioxidant activity.

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Peptide exhibited radical scavenging properties, reducing capacity and chelating effect.

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Intense proteolysis caused lower angiotensin I-converting enzyme inhibitory activity.

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Bioactive peptides were generated from α_s1-casein and β-casein.

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Ripening process of Gouda cheese results in a product with functional potential.

In Mexico, local ripened cheeses such as Chihuahua, Ranchero, and Cotija are produced, being consumed in great quantities together with imported cheeses. Proteolysis that takes place during ripening generates bioactive peptides; in this way the cheese acquires potential as a functional food. The ripening process of Gouda cheese was studied based on its bromatological and sensorial properties, bioactivity, and peptide profile. Ripened cheese met bromatological standard parameters and showed higher overall acceptability. After 90 days, bioactivity reached maximum values for radical scavenging (6.6%), ferric reducing power (11.2%), metal chelating effect (49%), and angiotensin I-converting enzyme inhibitory activity (66.2%). Eight peptides were identified, four from α_S1-casein, f(1–9, 1–13, 1–14, and 25–36), and four from β-casein, f(11–28, 60–63, 193–209, and 197–205). Ripening of Gouda cheese results in a product with functional potential due to the presence of peptides with biological activity. Additionally, the methodology proposed in this work could be used by the dairy industry to monitor the manufacturing process and ripening of other types of cheeses.

Textural and Functional Properties of Skimmed and Whole Milk Fermented by Novel Lactiplantibacillus plantarum AG10 Strain Isolated from Silage

Milk fermentation by lactic acid bacteria both enhances its nutritional value and provides probiotic strains to correct the intestinal microflora. Here, we show the comparative analysis of milk fermented with the new strain, Lactiplantibacillus plantarum AG10, isolated from silage and the industrial strain Lactobacillus delbrukii subs. bulgaricus. While the milk acidification during fermentation with L. plantarum AG10 was lower compared with L. bulgaricus, milk fermented with L. plantarum AG10 after a 14-day storage period retained a high level of viable cells and was characterized by an increased content of exopolysaccharides and higher viscosity. The increased EPS production led to clot formation with higher density on microphotographs and increased firmness and cohesiveness of the product compared with L. bulgaricus-fermented milk. Furthermore, the L. plantarum AG10-fermented milk exhibited increased radical-scavenging activity assuming lower fat oxidation during storage. Taken together, these data suggest that L. plantarum AG10 seems to be a promising starter culture for dairy products with lowered levels of lactic acid, which is important for people with increased gastric acid formation.

Amino Acid Composition of Milk from Cow, Sheep and Goat Raised in Ailano and Valle Agricola, Two Localities of 'Alto Casertano' (Campania Region)

Cow, sheep and goat raw milk raised in Ailano and Valle Agricola territories (‘Alto Casertano’, Italy) were characterized (raw proteins, free and total amino acids content) to assess milk quality. Raw milk with the highest total protein content is sheep milk followed by goat and cow milk from both localities. Total amino acid content in cow, goat and sheep raw milk is 4.58, 4.81 and 6.62 g per 100 g, respectively, in which the most abundant amino acid is glutamic acid (~20.36 g per 100 g of proteins). Vice versa, the free amino acids content characteristic profiles are different for each species. In particular, the most abundant free amino acid in cow, sheep and goat raw milk is glutamic acid (9.07 mg per 100 g), tyrosine (4.72 mg per 100 g) and glycine (4.54 mg per 100 g), respectively. In addition, goat raw milk is a source of taurine (14.92 mg per 100 g), retrieved in low amount in cow (1.38 mg per 100 g) and sheep (2.10 mg per 100 g) raw milk. Overall, raw milk from ‘Alto Casertano’ show a high total protein content and are a good source of essential amino acids.

Production of Bovine Equol-Enriched Milk: A Review

Simple Summary

Milk and dairy products contain many substances beneficial to human health; moreover, the contents of some of these substances can be enhanced. This is also the case of isoflavones which are compounds of plant origin that can be ingested and metabolized by cattle and, subsequently, secreted into bovine milk. An especially healthful substance called equol is ranked among isoflavone metabolites, commonly produced in the digestive tract of cattle. Equol content in milk can be modified by using feedstuffs with different contents of isoflavones or by milk processing and storage.

Abstract

Milk and dairy products are important sources of nutrients in the human diet because they contain a number of essential substances and other biologically active components. Many of these substances can be modified, and thus offer opportunities to use milk and dairy products as functional food. Isoflavones are particularly important in human nutrition due to their diverse pharmacological and antioxidant properties. The clinical effectiveness of isoflavone-rich products is believed to be dependent on their ability to metabolize daidzein to equol, which may directly exert cancer preventive effects. However, only approximately 30–40% of humans are able to produce equol, while animals, in general, produce equol. Equol is the predominant product of bacterial metabolism of isoflavones and can be found in various amounts in some food of animal origin, especially in milk. Therefore, milk and dairy products can be considered to be sources of equol for humans who are not able to produce this metabolite. When the content of isoflavones in milk is to be modified, two groups of factors should be considered, i.e., dietary factors that include the source of isoflavones and the processing effects on feedstuffs and animal factors that include the intake of isoflavones, ruminal and postruminal changes, and the health and physiological status of animals. The approximate content of isoflavones in milk can be predicted using carry-over rates for different dietary sources or using a formula that describes the relationship between equol concentration in milk and formononetin intake. Processing and storage can affect the content and profile of isoflavones in milk and dairy products.

Cheese as a functional food for older adults: comparing the bioactive properties of different cheese matrices following simulated gastrointestinal in vitro digestion

Age-related changes to the gastrointestinal tract (GIT) can impact how food is digested. Studying the effects of these changes can help identify functional foods for older adults. Cheese was digested using two simulated gastrointestinal in vitro digestion (SGID) models representing adult and elderly gastro-intestinal conditions. Antioxidant capacity was measured using DPPH, FRAP and TPC assays. The ability of cheese to inhibit digestive enzymes was determined by the α-glucosidase and lipase inhibition assays. Digestive aging influenced the bioactivity of cheese, as elderly digestates had significantly lower (p < 0.05) antioxidant, α-glucosidase and lipase inhibitory properties compared to adult digestates. However, soft cheese (feta, goats', brie) demonstrated greatest potential with comparable radical scavenging properties and lipase inhibition, greatest FRAP and α-glucosidase inhibitory potential. Despite age-related changes, the bioactive properties of cheese were evident following digestion with an older adult SGID model, suggesting cheese has potential as a functional food for older adults.

Nutraceuticals in Neurological Disorders

Neurological diseases are one of the major healthcare issues worldwide. Posed lifestyle changes are associated with drastically increased risk of chronic illness and diseases, posing a substantial healthcare and financial burden to society globally. Researchers aim to provide fine treatment for ailing disorders with minimal exposed side effects. In recent decades, several studies on functional foods have been initiated to obtain foods that have fewer side effects and increased therapeutic activity. Hence, an attempt has been made to unravel several extraction techniques to acquire essential bioactive compounds or phytochemicals from therapeutically active food products. This has led to the conception of the term functional foods being meddled with other similar terms like "pharmafoods," "medifoods", "vitafoods", or "medicinal foods". With a dire need to adhere towards healthy options, the demand of nutraceuticals is widely increasing to combat neurological interventions. An association between food habits and the individual lifestyle with neurodegeneration has been manifested, thereby proposing the role of nutraceuticals as prophylactic treatment for neurological interventions. The current review covers some of the major neurological disorders and nutraceutical therapy in the prevention of disease.

Effects of Fat Supplementation in Dairy Goats on Lipid Metabolism and Health Status

Simple Summary

There is an increasing demand for information on the nutraceutical properties of food. Due to its bioactive components and high digestibility, goat milk is an excellent functional food. Dietary fat supplementation can further enrich the value of goat milk by modifying its acidic profile. Nevertheless, animal health can also benefit from lipids supplied with rations. In this review, the relationships between dietary fats and goat health status are summarized. Particular attention is paid to describing the effects of specific fatty acids on lipid metabolism and immune functionality.

Abstract

Fat supplementation has long been used in dairy ruminant nutrition to increase the fat content of milk and supply energy during particularly challenging production phases. Throughout the years, advances have been made in the knowledge of metabolic pathways and technological treatments of dietary fatty acids (FAs), resulting in safer and more widely available lipid supplements. There is an awareness of the positive nutraceutical effects of the addition of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) to fat supplementation, which provides consumers with healthier animal products through manipulation of their characteristics. If it is true that benefits to human health can be derived from the consumption of animal products rich in bioactive fatty acids (FAs), then it is reasonable to think that the same effect can occur in the animals to which the supplements are administered. Therefore, recent advances in fat supplementation of dairy goats with reference to the effect on health status have been summarized. In vivo trials and in vitro analysis on cultured cells, as well as histological and transcriptomic analyses of hepatic and adipose tissue, have been reviewed in order to assess documented relationships between specific FAs, lipid metabolism, and immunity.

The "Grass-Fed" Milk Story: Understanding the Impact of Pasture Feeding on the Composition and Quality of Bovine Milk

Milk is a highly nutritious food that contains an array of macro and micro components, scientifically proven to be beneficial to human health. While the composition of milk is influenced by a variety of factors, such as genetics, health, lactation stage etc., the animal's diet remains a key mechanism by which its nutrition and processing characteristics can be altered. Pasture feeding has been demonstrated to have a positive impact on the nutrient profile of milk, increasing the content of some beneficial nutrients such as Omega-3 polyunsaturated fatty acids, vaccenic acid, and conjugated linoleic acid (CLA), while reducing the levels of Omega-6 fatty acids and palmitic acid. These resultant alterations to the nutritional profile of "Grass-Fed" milk resonate with consumers that desire healthy, "natural", and sustainable dairy products. This review provides a comprehensive comparison of the impact that pasture and non-pasture feeding systems have on bovine milk composition from a nutritional and functional (processability) perspective, highlighting factors that will be of interest to dairy farmers, processors, and consumers.

Milk and Dairy Products and Their Nutritional Contribution to the Average Polish Diet

The main aim of this study was to identify the dairy sources of energy and 44 nutrients in the average Polish diet. Our research included: carbohydrates, protein, total fat, saturated fatty acids (SFA), monounsaturated fatty acids (MUFA), polyunsaturated fatty acids (PUFA), cholesterol, 18 amino acids, 9 minerals, and 10 vitamins. The analysis was conducted based on the data from the 2016 Household Budget Survey, a representative sample of the Polish population (i.e., 36,886 households). The category of milk and dairy products was divided into three main groups (i.e., milk, cheeses, and yoghurts, milk drinks and other dairy products) and seven sub-groups (i.e., whole milk, reduced fat milk, condensed and powdered milk, ripened and melted cheese, cottage cheese, yoghurts, milk drinks and other dairy products). Milk and dairy products provided 9.1% of the total energy supply. A high share (above 20%) in the supply of nutrients was noted in the case of calcium (54.7%), riboflavin (28.1%), vitamin B12 (26.1%), and phosphorus (24.6%). Supply at the level of 10-20% was observed for protein, SFA, zinc, total fat, cholesterol, potassium, magnesium, and vitamin A. Of the amino acids, the share above 20% from dairy category was recorded in the case of 6 amino acids (proline, tyrosine, serine, lysine, valine, and leucine) and at the level of 10-20% for 10 amino acids (isoleucine, histidine, threonine, tryptophan, phenylalanine, methionine, glutamic acid, aspartic acid, alanine, and arginine).

Dairy foods and positive impact on the consumer's health

The objective of the present chapter was to demonstrate the state of the art in the recent advances in nutritional and functional components of dairy products research. In this chapter, the main mechanisms responsible and essential for a better understanding of nutritional and functional values of the components of milk and dairy products are highlighted. It also includes a discussion about the positive impacts of fermented milk, cheese, butter, ice cream, and dairy desserts components on the consumer's health.

Concepts, benefits and perspectives of functional dairy food products

The rising awareness of the consumers towards the health benefits of food has resulted in the development of the so-called functional foods. These added value products which refer to prevention and/or therapeutic effects of food beyond its nutritional value, are especially useful for health improvement and reduction of medical care costs. The combination between health and nutrition and its potential to improve the quality of life has become one of the key attention points of consumers who are aware of and are seeking nutritional solutions to their health concerns. Milk and dairy products have been used in human nutrition for thousands of years, providing important nutrients for the human body such as proteins, fats and calcium. It is now widely recognized that in addition to their basic nutritive role they also exert functional properties beneficial for human health, so the development of functional dairy products is one of the fastest growing areas in the dairy industry as well as one of the largest sectors in the global market of functional foods. This review provides a brief overview of the health benefits and the natural functionality of dairy products as well as the challenges together with the future perspectives of their application as delivery vehicles for beneficial compounds to the human body. Keywords: functional foods, milk, dairy products

Antibacterial and antiproliferative peptides in synbiotic yogurt-Release and stability during refrigerated storage

The search for alternative therapeutics is on the rise due to the extensive increase in bacterial resistance to various conventional antibiotics and side effects of conventional cancer therapies. Bioactive peptides released from natural sources such as dairy foods by lactic acid bacteria have received attention as a potential source of biotherapeutic peptides. However, liberation of peptides in yogurt depends on proteolytic activities of the cultures used. Thus, this research was conducted to establish generation of inhibitory peptides in yogurt against pathogenic bacteria and cancer cells during storage at 4°C for 28d. Water-soluble crude peptide extracts were prepared by high-speed centrifugation of plain and probiotic yogurts supplemented with or without pineapple peel powder (PPP). The inhibition zones against Escherichia coli and Staphylococcus aureus by PPP-fortified probiotic yogurt at 28d of storage were, respectively, 25.89 and 11.72mm in diameter, significantly higher than that of nonsupplemented control yogurts. Antiproliferative activity against HT29 colon cancer cells was also significantly higher in probiotic yogurt with PPP than in nonsupplemented probiotic yogurt. Overall, crude water-soluble peptide extracts of the probiotic yogurt with PPP possessed stronger inhibitory activities against bacteria and cancer cells than controls, and these activities were maintained during storage. However, activities were lowered substantially during in vitro gastrointestinal digestion. These findings support the possibility of utilizing dairy-derived bioactive peptides in the development of a superior alternative to the current generation of antibacterial and anticancer agents, as well as a functional ingredient in foods, nutraceuticals, and pharmaceuticals.

Effect of refrigerated storage on probiotic viability and the production and stability of antimutagenic and antioxidant peptides in yogurt supplemented with pineapple peel

Fruit by-products are good resources of carbohydrates, proteins, vitamins, and minerals, which may function as growth nutrients for probiotic bacteria. This research aimed at evaluating effects of pineapple peel powder addition on the viability and activity of Lactobacillus acidophilus (ATCC 4356), Lactobacillus casei (ATCC393), and Lactobacillus paracasei ssp. paracasei (ATCC BAA52) in yogurts throughout storage at 4°C for 28d. Plain and probiotic yogurts supplemented with or without pineapple peel powder or inulin were prepared. The probiotic counts in supplemented yogurts at 28d of storage ranged from 7.68 and 8.03 log cfu/g, one log cycle higher compared with nonsupplemented control yogurt. Degree of proteolysis in synbiotic yogurts was significantly higher than plain yogurts and increased substantially during storage. Crude water-soluble peptide extract of the probiotic yogurt with peel possessed stronger antimutagenic and antioxidant activities [evaluated measuring reducing power and scavenging capacity of 1,1-diphenyl-2-picrylhydrazyl; 2,2'-azino-bis(3-ethyl benzothiazoline-6-sulfonic acid), and hydroxyl radicals] than control and maintained during storage. Pineapple peel, a by-product of juice production, could be proposed as a prebiotic ingredient in the manufacture of yogurts with enhanced nutrition, and functionality.

Fatty acid content, health and risk indices, physicochemical composition, and somatic cell counts of milk from organic and conventional farming systems in tropical south-eastern Mexico

Organic agriculture and livestock farming is claimed to promote animal welfare and can offer animal products with better hygienic-sanitary quality, based on principles of health, ecology, fairness, and care. However, no clear advantages of organic milk (OM) versus conventional milk (CM) from tropical conditions are available. The aims of the study were to determine fatty acid profile, health-promoting (HPI) and thrombogenic (TI) indices, physicochemical composition, and somatic cell counts (SCC) of OM and CM in tropical south-eastern Mexico. Female cross-breed cows (400-600 kg) were employed. CM had larger values of saturated fatty acids (SFA) and polyunsaturated fatty acid (PUFA) (63.6 %; 4.57 %) than OM (61.48 %; 4.22 %), while OM resulted in a larger value of monounsaturated fatty acid (MUFA) (34.3 %) than CM (31.7 %). HPI and TI showed that OM was more favorable than CM. Milk production and physicochemical composition (PC) as well as density had no significant difference, while SCC was significantly lower in OM than in CM on a monthly basis. These results showed that OM promotes a healthful and balanced diet, and is already produced by sustainable ecologic technologies employing traditional agrosilvopastoral management, which is more environmentally friendly and promotes ecological resilience.

Effect of Sicilian pasture feeding management on content of α-tocopherol and β-carotene in cow milk

This study was performed to evaluate α-tocopherol and β-carotene contents of pasture milk under ordinary Sicilian farming conditions. Fourteen dairy farms were allocated into 2 balanced groups on the basis of cultivated (CULT) or spontaneous (SPO) pasture type feeding. Bulk milk per farm was collected 4 times from February through April at 3-wk intervals. Pasture botanical and diet composition, diet nutritional quality, milk yield and composition were estimated each time. Pasture intake levels were calculated based on feed analyses, hay and concentrate amounts fed, and milk yield and chemical composition. According to pasture intake, the farms were split into low pasture intake (LPI; <29.5% of dry matter) and high pasture intake (HPI; >29.5% of dry matter) groups. Milk samples per farm were analyzed for α-tocopherol and β-carotene contents by HPLC. The SPO group had higher levels of α-tocopherol and β-carotene in milk (0.7 and 0.3 mg/L, respectively) and milk fat (19.0 and 7.5 mg/kg fat, respectively) compared with the CULT group in milk (0.5 and 0.2 mg/L, respectively) and milk fat (14.6 and 4.9 mg/kg, respectively). High pasture intake compared with LPI increased α-tocopherol in milk fat (18.0 and 16.0 mg/kg of fat, respectively). However, only in the SPO (not in CULT), HPI compared with LPI increased milk α-tocopherol (0.8 vs. 0.6 mg/L, respectively), milk β-carotene (0.3 vs. 0.2 mg/L, respectively), and milk fat β-carotene (8.4 vs. 6.6 mg/kg, respectively). Results may be related to the different botanical composition of the respective pasture types and pasture intake. Spontaneous pasture compared with CULT contained a higher mass proportion of Asteraceae, Fabaceae, Cruciferae, Euphorbiaceae, and Malvaceae plants. Milk and milk fat α-tocopherol levels were higher on test-days (TD)-1, TD-2, and TD-4 compared with TD-3. For HPI farms, milk fat β-carotene content was higher on the first 2 TD compared with the last 2 TD. These differences could be related to plant biological stage. On Sicilian dairy farms, the highest milk α-tocopherol and β-carotene contents may be obtained feeding high levels of SPO pasture in the spring.

Changes in milk and plasma fatty acid profile in response to fish and soybean oil supplementation in dairy sheep

An effective strategy for enhancing the bioactive fatty acids (FA) in sheep milk could be dietary supplementation with a moderate level of a combination of soybean oil with fish oil (SFO) without negative effects on milk yield and its chemical composition. Thus, the objective of this study was to determine the effects of a moderate forage diet supplementation with SFO on milk chemical composition and FA profile, as well as on plasma FA. Twelve dairy sheep were assigned to two homogenous sub-groups. Treatments involved a control diet without added oil, and a diet supplemented with 23·6 g soybean oil and 4·7 g fish oil per kg dry matter (DM) of the total ration. The results showed that SFO diet had no effect on milk yield and chemical composition. In blood plasma the concentrations oftrans-11C18:2(VA), C18:2n-6, C20:5n-3(EPA) and C22:6n-3(DHA) were significantly higher while those of C14:0, C16:0and C18:0were lower in sheep fed with SFO diet compared with control. The SFO supplementation of sheep diet increased the concentrations of VA,cis-9, trans-11C18:2CLA,trans-10, cis-12, C18:2CLA, EPA, DHA, monounsaturated FA (MUFA), polyusaturated fatty acids (PUFA) andn-3 FA and decreased those of short chain FA (SCFA), medium chain FA (MCFA), the saturated/unsaturated ratio and the atherogenicity index value in milk compared with the control. In conclussion, the SFO supplementation at the above levels in a sheep diet, with moderate forage to concentrate ratio, improved the milk FA profile from human health standpoint without negative effects on its chemical composition.

NutriChip: nutrition analysis meets microfluidics

This focus article introduces the concept of NutriChip, an integrated microfluidic platform for investigating the potential of the immuno-modulatory function of dairy food. The core component of the NutriChip is a miniaturized artificial human gastrointestinal tract (GIT), which consists of a confluent layer of epithelial cells separated from a co-culture of immune cells by a permeable membrane. This setting creates conditions mimicking the human GIT and allows studying processes that characterize the passage of nutrients though the human GIT, including the activation of immune cells in response to the transfer of nutrients across the epithelial layer. The NutriChip project started by developing a biologically active in vitro cellular system in a commercial Transwell co-culture system. This Transwell system serves as a reference for the micro-scale device which is being developed. The microfluidic setup of NutriChip allows monitoring of the response of immune cells to pro-inflammatory stimuli, such as lipid polysaccharide (LPS), and to the application of potentially anti-inflammatory dairy food. This differential response will be quantified by measuring the variation in expression of pro-inflammatory cytokines, including interleukin 1 (IL-1) and interleukin 6 (IL-6), secreted by the immune cells, and this is achieved by using a dedicated optical imager. A series of dairy products will be screened for their anti-inflammatory properties using the NutriChip system and, finally, the outcome of the NutriChip will be validated by a human nutrition trial. Therefore, the NutriChip platform offers a new option to evaluate the influence of food quality on health, by monitoring the expression of relevant immune cell biomarkers.

In vitro evaluation of the fermentation properties and potential prebiotic activity of caprine cheese whey oligosaccharides in batch culture systems

The prebiotic effect of oligosaccharides recovered and purified from caprine whey, was evaluated by in vitro fermentation under anaerobic conditions using batch cultures at 37°C with human faeces. Effects on key gut bacterial groups were monitored over 24 h by fluorescence in situ hybridization (FISH), which was used to determine a quantitative prebiotic index score. Production of short-chain fatty acids (SCFAs) as fermentation end products was analyzed by high-performance liquid chromatography (HPLC). Growth of Bifidobacterium spp was significantly higher (P ≥ 0.05) with the purified oligosaccharides compared to the negative control. Lactic and propionic acids were the main SCFAs produced. Antimicrobial activity of the oligosaccharides was also tested, revealing no inhibition though a decrease in Staphylococcus aureus and Escherichia coli growth. These findings indicate that naturally extracted oligosaccharides from caprine whey could be used as new and valuable source of prebiotics.

Debittering of Protein Hydrolysates by Lactobacillus LBL-4 Aminopeptidase

Yoghurt strain Lactobacillus LBL-4 cultivated for 8–10 h at pH ~6.0 was investigated as a considerable food-grade source of intracellular aminopeptidase. Cell-free extract manifesting >200 AP U/l was obtained from cells harvested from 1 L culture media. Subtilisin-induced hydrolysates of casein, soybean isolate, and Scenedesmus cell protein with degree of hydrolysis 20–22% incubated at 45°C for 10 h by 10 AP U/g peptides caused an enlarging of DH up to 40–42%, 46–48%, and 38–40% respectively. The DH increased rapidly during the first 4 h, but gel chromatography studies on BioGel P-2 showed significant changes occurred during 4–10 h of enzyme action when the DH increased gradually. After the digestion, the remained AP activity can be recovered by ultrafiltration (yield 40–50%). Scenedesmus protein hydrolysate with DH 20% was inoculated by Lactobacillus LBL-4 cells, and after 72 h cultivation the DH reached 32%. The protein hydrolysates (DH above 40%) obtained from casein and soybean isolate (high Q value) demonstrated a negligible bitterness while Scenedesmus protein hydrolysates (low Q value) after both treatments were free of bitterness.