Vitamin B6 in Raw and Fried Chicken by HPLC

An isocratic anion exchange, high performance liquid chromatography (HPLC) method was developed to analyze for five of the six vitamers of B₆. Recoveries of the B₆ vitamers in a standard were 100% to 97%. Recoveries in fried chicken breast ranged from 96% for pyridoxal phosphate to 102% for pyridoxine (PN). Recoveries in raw chicken breast ranged from 86% for pyridoxamine to 102% for PN. Processing chicken by frying reduced the total vitamer by 6.5%. Vitamers of B₆ were relatively stable to frying.     

Microbial Biosensor System for Rapid Determination of Vitamin B6

A microbial biosensor system was based on an immobilized microorganism (Succharomyces uvarum 4288 ATCC9080) and Clark-type oxygen electrode consisting of a platinum cathode, lead anode, alkaline electrolyte, and an oxygen permeable Teflon membrane. The determination was based on the respiratory activity of the microorganism in presence of vitamin B₆. Optimum conditions were: concentration of immobilized cells on membrane: OD₆₆₀, = 0.05, temperature: 30°C. When oxygen permeable Teflon membranes (0.5 mil and 2.0 mil) were employed, relationships between vitamin B₆, (pyridoxine) and current decrease were linear in the range of 0.5 ng/mL-2.5 ng/mL and 2.5 ng/mL-12.5 ng/mL, respectively. One assay could be completed within 15 min. This system provided rapid and simple determinations of vitamin B₆ in marine products with good correlation to traditional microbial assay values.     

High Performance Liquid Chromatographic Determination of Carbohydrates in Raw and Cooked Vegetables

The soluble sugar contents of 17 raw and cooked vegetables were determined by TLC and HPLC. In general, the soluble carbohydrate content of vegetables is low. For raw materials the highest content was found in carrot, red cabbage, egg plant, green bean and leek. Upon cooking the glucose, fructose and total sugar contents decrease and this diminution is more drastic in the case of frying. The amount of sucrose, except in the case of carrot, egg plant and green bean, increases with cooking. The maltose content of the broad bean increases in the culinary process.     

Vitamin B6 In Ready-To-Eat Cereals: Analysis By High Performance Liquid Chromatography

Twenty-four ready-to-eat cereals obtained locally were analyzed for their vitamin B₆ content by a recently developed high performance liquid chromatographic (HPLC) procedure. The method uses sulfo-salicylic acid as an extraction agent with subsequent qualitative and quantitative analysis by anion exchange chromatography. All six forms of vitamin B₆ plus their metabolite, pyridoxic acid, can be identified and quantified. Spot checks of the results obtained with this method and with a radiometric-microbiological assay give agreement to within 5%. On the other hand, disagreements of up to 38% are found on comparison with the standard AOAC microbiological procedure used by a commercial laboratory. The results indicate no significant variations between boxes within the same lot, but in one-third of the cereals tested, significant variations were found from lot to lot.     

High Performance Liquid Chromatographic Analysis of Riboflavin (Vitamin B2) with Visible Absorbance Detection in Italian Cheeses

A high-performance liquid chromatographic method for riboflavin determination in cheese samples was developed. Reverse phase conditions were used, i.e., a C-18 column isocratically eluted with an acetonitrile water mixture (20:80). A shift of the detection wavelength from 267 to 446 nm was proposed as a simple and very effective means for circumventing the problem of incomplete resolution of riboflavin from interfacing peaks. The detection limit of riboflavin was 2.5 ng, a value well above the level required for determining the riboflavin content in cheese samples. From both high- and low-fat cheese, the riboflavin recovery was the same (90.2%). The riboflavin content of several different Italian cheeses was determined.     

Protein-Protein Interactions Between Soybean Beta-conglycinin (B1-B6) and Myosin

Protein-protein interactions between soybean beta-conglycinin (B₁- B₆) and myosin were studied by turbidity, solubility and SDS-poly- acrylamide gel electrophoresis (SDS-PAGE) analysis. Turbidity and solubility studies showed that, under the experimental conditions used, these proteins interacted at temperatures between 60° and 100°C, while SDS-PAGE analysis indicated that the interaction also occurred at 50°C. The interasction was such that no detectable complexing between these two proteins was observed. The presence of beta-conglycinin resulted in diminished aggregations of myosin heavy chains between 50° and 100°C.     

Optimisation of baking parameters of chapati with respect to vitamin B1 and B2 retention and quality

Vitamin losses during processing of cereal grains and their food products play an important role in human vitamin intake. Therefore, experiments were conducted to optimise the baking parameters for chapati, a flat unleavened, hot-plate-baked product of Asian diet. In the experiments, whole-wheat flour (100% extraction rate) was used for the preparation of chapaties. Central composite rotatable design with three independent variables (thickness of dough sheet, time as well as temperature of baking) at five levels and nine dependent variables, i.e. vitamin B₁ and B₂ content, textural properties and overall acceptability scores, were used to conduct the experiments. The ranges for three independent variables were: thickness, 2.5–4.5 mm; time, 2.0–3.0 min; and temperature, 200–240 °C. Thickness of the dough sheet had a significant ( P  ≤ 0.05) positive effect on vitamin retention, while the temperature had greater negative effect as compared with the time of baking. Based on compromise optimisation, optimum conditions for baking of chapati, especially with respect to vitamin retention were: thickness of dough sheet 3.2 mm, time of baking 2.1 min and baking temperature 216.3 °C.     

A SIMPLE SOLID-PHASE RADIOIMMUNOASSAY FOR AFLATOXIN B1

A solid-phase radioimmunoassay (RIA) for aflatoxin B₁ (afla B₁) was developed. This method involved the incubation of afla B₁, both labelled and unlabelled, with immunoglobulin (IgG)-sepharose gel which was prepared by conjugation of the IgG highly specific to afla B₁ with CNBr-activated sepharose gel, followed by a filtration step. The binding capacity was determined by counting the radioactivity in the filtrate. Studies with different afla B₁ analogues revealed that the IgG-gel bound most effectively with B₁. Binding of afla B₂, G₁, G₂, and aflatoxicol to the IgG-gel was less effective in comparison with the IgG before coupling. Between 0.5–5.0 ng per assay, the displacement of radioactivity from the gel was directly proportional to the amount of afla B₁ present. Using a simple extraction procedure without clean-up step, the recovery yields for afla B₁ in the contaminated corn or wheat at levels of 5 ppb or above were above 60%.     

Vitamin B12 Activity in Miso and Tempeh

The USP microbiological assay with L. leichmannii, ATCC 7830, was used to determine vitamin B₁₂ activity in light rice miso, dark rice miso, barley miso, tempeh and tempeh burger. Unpasteurized misos were found to have the highest B₁₂ content, averaging 0.21 μg/ 100g. Vitamin B₁₂ activity in miso ranged from a high of 0.25 μg/ 100g in barley miso to a low of 0.15 μg/100g in light rice miso. Pasteurized tempeh contained 0.12 μg vitamin B₁₂ per 100g food. Tempeh burger contained 0.06 to 0.11 μg vitamin B₁₂ per 100g food. The variation in vitamin B₁₂ activity found in these products may be due to different conditions used or produced during fermentation. Collaborative studies are needed and assessment of vitamin B₁₂ pseudoform activity before these foods can be considered a source of vitamin B₁₂.     

Isolation and Structure of a New Vitamin B6 Conjugate in Rice Bran

A major form of vitamin B₆ in rice bran was isolated by various chromatographic techniques as colorless powder. It was identified as 5′-O-[6-O-((+)-5-hydroxy-dioxindole-β-acetyl)-β-cellobiosyl] pyridoxine by spectroscopy, and enzymatic and chemical hydrolyses.     

Comparison of Sample Storage Methods for Vitamin B6, Assay in Broiler Meats

Five methods were compared for storage stability of vitamin B₆ in broiler meat samples. Maximum retention of vitamin B₆ was observed in the N₂-packed freeze-dried samples at -34°C (101–103% up to 20 mo). Good retentions occurred in the intact tissues of half birds at -34°C (90% in 16 mo) and in ground meat samples (200g portions) at -34°C (91% up to 12 mo). Significantly lower retentions were found in freeze-dried samples stored at room temperature (85–77% in 1–5 mo, respectively) and for ground meat small portion samples (5g) at -34°C (84–72% in 3–5 mo, respectively).     

A Reasearch Note VITAMIN B6 IN PORK MUSCLE COOKED IN MICROWAVE AND CONVENTIONAL OVENS

Loin sections of pork muscle were heated to 75 or 85°C internal temperatures in microwave or conventional electric ovens. Cooking losses and time, percentage moisture and total vitamin B₆ were determined. Cooking time was longer, total cooking loss less and moisture content greater for pork cooked in an electric oven than for that cooked in a microwave oven. Differences in vitamin B₆ due to type of oven or internal temperature were small and not significant when calculated on a cooked weight basis. When calculated on a dry weight basis samples cooked in the conventional oven contained more vitamin B₆ than did those cooked by a microwave oven.     

PHYTIC ACID INHIBITS the PRODUCTION of AFLATOXIN B1

Phytic acid inhibition of Aspergillus flavus aflatoxin B₁ production is well observed. Although this fungus grew well in Czapak-Dox medium, mycotoxin production was eliminated by adding a small amount of phytic acid. Possible reasons are discussed, and the importance of some metallic ions is observed. Results suggested that phytate may be an effective anti-AFB₁ agent for preventing the contamination of the fungus.     

Effect of Processing and Storage Conditions on the Fate of Vitamins B1, B2, and C and on the Shelf-Life of Goat's Milk

Goat's milk was heat-processed under different time-temperature conditions of pasteurization and sterilization. Losses of thiamin, riboflavin, and total vitamin C in HTST, Flash, and UHT were less than that by LTLT and Autoclave. Also residual oxygen in the milk affected the loss of total vitamin C during storage. A longer shelf-life of pasteurized milk was obtained with HTST, HTST overpasteurization, and Flash process; however, there was no significant difference between UHT and Autoclave sterilized products. From the above results, HTST pasteurization was considered the best process to preserve milk quality.