Dietary Food Products Research Articles

Modified milk powder supplemented with immunostimulating whey protein concentrate (IMUCARE) enhances immune function in mice

Some whey protein concentrates (WPCs) can act as immunostimulatory and anticancer dietary components when delivered as a major protein source to animals and human beings. In this study, we have investigated the effects of a known immunostimulatory WPC (IMUCARE) when delivered to mice in a modified milk powder (MMP), nutritionally balanced for young children (aged 1-3 years). Groups of BALB/c mice were fed with MMP-based diets with or without IMUCARE WPC supplemented at 10.5 g/100 g of diet for periods of 4 weeks. Ex vivo immunologic assays indicated that splenic lymphoproliferative responses, as well as blood and peritoneal leukocyte phagocytic activity, were elevated in mice fed MMP supplemented with IMUCARE WPC, in comparison either to mice fed with MMP alone or to control mice that did not receive milk proteins. In contrast, both IMUCARE WPC–supplemented MMP and MMP alone were shown to stimulate enhanced humoral immunity, with significantly elevated serum and intestinal tract antibody responses to orally administered antigens being recorded in these mice compared with animals fed with nonmilk protein. These results confirm that IMUCARE WPC retains immunoenhancing efficacy when delivered in a nutritionally balanced milk product and additionally identifies nutritionally balanced MMP as a potential immunostimulatory dietary food product.

Severe oral allergy syndrome and anaphylactic reactions caused by a Bet v 1– related PR-10 protein in soybean, SAM22

Background: Anaphylactic reactions to soy products have been attributed to stable class 1 food allergens. Objective: IgE- mediated reactions to a soy- containing dietary food product in patients allergic to birch pollen were investigated. Methods: Detailed case histories were taken from 20 patients. Their sera were analyzed for IgE (UniCAP) specific for birch, grass, mugwort, the recombinant birch allergens rBet v 1 and rBet v2, and soy protein. Extracts from birch pollen, soy isolate, rBet v 1, and the recombinant PR-10 soy protein rSAM22 were coupled to paper disks or nitrocellulose for IgE measurements (enzyme allergosorbent test) or Western blot analysis. Enzyme allergosorbent testing, Western blot inhibition, and histamine release studies were performed with the same allergens. Results: Most patients (17/20) experienced facial, oropharyngeal, and/or systemic allergic symptoms within 20 minutes after ingesting the soy product for the first time. Birch pollen allergy (16/20) was common, along with oral allergy syndrome to apple (12/20) or hazelnut (11/20). IgE levels to birch and Bet v 1 but not to other inhalants were high in 18 of 20 patients. Significant IgE binding to rSAM22 occurred in 17 of 20 patients. Blot experiments with the soy isolate revealed IgE- binding bands at 17 kd (15/20), 22 kd (1/20), and 35 to 38 kd (2/20); the former was inhibited by preincubation of the sera with rBet v 1 or rSAM22. Birch extract and soy isolate, rBet v 1, and rSAM22 induced dose-dependent histamine release in the nanomolar range. Conclusion: Immediate-type allergic symptoms in patients with birch pollen allergy after ingestion of soy protein–containing food items can result from cross- reactivity of Bet v 1 – specific IgE to homologous pathogenesis-related proteins, particularly the PR-10 protein SAM22. (J Allergy Clin Immunol 2002;110:797-804.)

An improved FIA biosensor for the determination of aspartame in dietary food products.

A flow injection analysis (FIA) biosensor system was developed for the determination of the artificial sweetener aspartame (L-aspartyl-L-phenylalanine methyl ester). The system consisted of an enzyme column of pronase immobilized on activated arylamine glass beads and a L-amino acid oxidase electrode connected in series. The dipeptide bond of aspartame was cleaved by immobilized pronase to release phenylalanine, which was in turn monitored by the enzyme electrode that used L-amino acid oxidase immobilized on a preactivated nylon membrane in combination with an amperometric electrode (platinum vs silver/silver chloride, 700 mV). The response of the FIA biosensor was linear up to 1 mM aspartame with a lower detection limit of 25 microM and had good reproducibility (rsd 0.3%). The FIA biosensor was stable for at least 30 h of continuous use at Tr. Each assay takes 4 min giving a sample throughput of 15 h-1. When applied to aspartame in dietary food products the results obtained agreed well with those reported by the product manufacturers.

Determination of aspartame in dietary food products by a FIA biosensor

A flow injection analysis (FIA) biosensor system was developed for the determination of the artificial sweetener aspartame (N- l-α-aspartyl- l-phenylalanine methyl ester). The system consisted of two enzyme columns, containing purified peptidase and aspartate aminotransferase respectively, immobilized on activated aminopropyl glass beads and an enzyme electrode connected in series. The dipeptide bond of aspartame was cleaved by immobilized peptidase to release aspartic acid which was in turn transaminated by aspartate aminotransferase. The glutamate produced by transamination was monitored by the enzyme electrode which used l-glutamate oxidase immobilized on a nylon membrane in combination with a hydrogen peroxide electrode. The response of the FIA biosensor was linear up to 1 m m aspartame with a lower detection limit of 20 μ m and had good reproducibility (r.s.d.2·2%). The FIA biosensor was stable for at least 30 h of continuous use at room temperature and the immobilized enzymes were stable for at least 1 month when stored in buffer at 4°C. Each assay takes ca. 7–8 min giving a sample throughput of 8 h −1. When applied to aspartame measurements in dietary food products, the results obtained agreed well with those reported by the product manufacturer.

Enzymatic assay technique for the determination of aspartame

An enzymatic assay technique was developed for the determination of the artificial sweetener aspartame. The peptide bond of aspartame was first cleaved by peptidase to release aspartic acid. In the presence of α-ketoglutarate, aspartic acid was then transaminated by aspartate aminotransferase to glutamate. The reaction was monitored by following the oxygen consumption during the enzymatic oxidation of glutamate by glutamate oxidase. A linear relationship between oxygen consumption and aspartame concentration up to 200 μM was obtained. The assay technique was applicable to the determination of aspartame in a variety of dietary food products. The results obtained agreed well with those determined by liquid chromatography and those reported by the product manufacturers.

Enrichment of Special Dietary Food Products

Enrichment of Special Dietary Food Products