Fat globule membranes in ewes' milk: The main enzyme activities during lactation

A trial was carried out on seven Massese ewes, from which individual milk samples were taken during lactation. All the enzyme activities investigated (oxidase activity of xanthine oxidoreductase, gamma-glutamyltranspeptidase, alkaline phosphatase and 5′-nucleotidase) were affected by the lactation phase, with the exception of the dehydrogenase activity of xanthine oxidoreductase (XOR). A higher oxidase activity (XO) of XOR was found when the diameter of milk fat globules was smaller. In addition, the absence of XO in colostrum led to the hypothesis that its antibacterial role is independent of its activity. The increase in alkaline phosphatase activity during lactation requires further research to better define the criteria for pasteurised sheep milk.     

Heat Curing of Soy Protein Films at Atmospheric and Sub-atmospheric Conditions

ABSTRACT: The effect of heat curing at atmospheric or subatmospheric conditions on selected properties (moisture content, water vapor permeability (WVP), color, tensile strength (TS), elongation (E), and total soluble matter (TSM) content) of cast soy protein isolate films was investigated. Films were heat cured at 85 °C for 6, 12, 18, or 24 h at absolute pressures of 101.3, 81.32, or 61.32 kPa. Heat-cured films had increased (P < 0.05) TS and decreased (P < 0.05) WVP and E compared to control, unheated films. Heat treatment under vacuum reduced the WVP of films faster than heat curing at atmospheric pressure. High TS values, low E values, and low TSM values were also reached within short heating time under vacuum. However, vacuum treatment increased the size and number of cavities in cured films as evidenced by scanning electron micrographs.     

Effect of modified atmosphere packaging on the shelf-life of coated, whole and sliced mushrooms

Whole and sliced fresh mushrooms (Agaricus bisporus) were packaged with PVC wrap or two polyolefins (PD-941 and PD-961) films after coating with CaCl₂ and chitosan. Package gas composition, color, weight loss and maturity were measured during storage at 12 °C and 80%RH. For PD-961, the highest in-package concentration occurred during the first day of storage regardless of treatments, while wrap and PD-941 showed varying degrees in-package concentration with different processes and coatings. The whiteness of whole mushrooms varied significantly with the type of coating, but not with the type of films. The extent of darkening was greater in coated whole mushrooms than in sliced ones. Weight loss occurred in all packages and varied from 3 (g/100 g) to about 7 (g/100 g) after 6 days of storage. Due to a lower permeability, PD-961 packages had the lowest weight loss. The type of packaging films significantly affected the maturity index, where PD-961 most effectively lowered maturity index for both whole and sliced mushrooms, thus extending the shelf-life. The type of coating did not appear to affect maturity index except for the wrap package where chitosan coating markedly lowered the maturity index of sliced mushrooms.     

Consumer Awareness and Interest Toward Sodium Reduction Trends in Korea

Reduction of dietary sodium intake by lowering amount of sodium in foods is a global industry target. Quantitative information on current consumer knowledge of sodium reduction trends in Korea is unknown. The objective of this study was to quantify the consumer knowledge and awareness of sodium and salt reduction in foods and to characterize consumer interest in health labeling on the food package. Additionally, comparison of consumer knowledge status between Korea and United States was followed. Consumers (n = 289) participated in an internet survey designed to gauge consumer knowledge and attitudes toward dietary sodium, the sodium content in representative food products (n = 27), and their interest toward specific health claims, including sodium labeling. Questions regarding demographics as well as consumption characteristics were asked. Sodium knowledge index and saltiness belief index were calculated based on the number of correct responses regarding the salt level and sodium content in given food products. Kano analysis was conducted to determine the role of nutrition labels in consumer satisfaction with products. Current consumer knowledge on the sodium content in food products was high, and consumers were adept at matching the sodium content with the salty taste intensity of food products. Consumers’ knowledge of the relationship between diets high in sodium and an increased risk of developing previously reported sodium‐related diseases, such as hypertension, coronary heart disease, kidney disease, and stomach cancer, were also high. Information on the nutrition panel that influences the consumer satisfaction (trans‐fat, sodium, ingredient list, and country of origin) as well as adjective‐nutrition claim pairs that appeal positively to purchase intent of the product were identified.     

Physicochemical and sensory characteristics of commercially available rice-based Doenjang and their correlation to consumer acceptability for Korean young adults

Food Science and Biotechnology - There is an increased demand for rice doenjang by consumers who are allergic to beans as well as for those seeking diverse flavors. The objective of this study was...     

Measuring oxidative DNA damage and DNA repair using the yeast comet assay

Chromosomal DNA damage can be a result of several processes and agents of endogenous or exogenous origin. These cause strand breaks or oxidized bases that lead to strand breaks, which relax the normally supercoiled genomic DNA and increase its electrophoretic mobility. The extent of DNA damage can be assessed by single cell gel electrophoresis, where the chromosomal DNA migration distance correlates with the extent of DNA damage. This technique has been used for a variety of applications with several organisms, but only a few studies have been reported for Saccharomyces cerevisiae. A possible reason for this absence is that low cellular DNA content could hamper visualization. Here we report an optimization of the comet assay protocol for yeast cells that is robust and sensitive enough to reproducibly detect background DNA damage and oxidative damage caused by hydrogen peroxide. DNA repair was observed and quantified as diminishing comet tail length with time after oxidative stress removal in a process well described by first‐order kinetics with a tail length half‐life of 11 min at 37 °C. This is, to our knowledge, the first quantitative measurement of DNA repair kinetics in S. cerevisiae by this method. We also show that diet antioxidants protect from DNA damage, as shown by a three‐fold decrease in comet tail length. The possibility of assessment of DNA damage and repair in individual cells applied to the model organism S. cerevisiae creates new perspectives for studying genotoxicity and DNA repair. Copyright © 2010 John Wiley & Sons, Ltd.     

Processing of Sapota (Sapodilla): Drying

ABSTRACT: The drying characteristics of sapota ( Achras zapota, cv , Kalipatti), a tropical fruit crop, were studied. Fruits were cut in sizes of half, quarter, and 5 mm slices and dried at temperatures of 55, 60, 65, and 70 °C in convection air and vacuum ovens. Moisture content of the fruit reduced from 72 to 78% (w.b) to 8.5 to 12.5% (w.b.) with drying times of 15 to 35 h in a convection air oven and of 14 to 31 h in a vacuum oven. Log and modified log models were fitted for the drying data. Empirical models were developed to predict drying constants as a function of drying temperature and sizes of samples with good correlation. Keywords: sapota, sapodilla, drying     

A motif detection and classification method for peptide sequences using genetic programming

An exploration of common rules (property motifs) in amino acid sequences has been required for the design of novel sequences and elucidation of the interactions between molecules controlled by the structural or physical environment. In the present study, we developed a new method to search property motifs that are common in peptide sequence data. Our method comprises the following two characteristics: (i) the automatic determination of the position and length of common property motifs by calculating the physicochemical similarity of amino acids, and (ii) the quick and effective exploration of motif candidates that discriminates the positives and negatives by the introduction of genetic programming (GP). Our method was evaluated by two types of model data sets. First, the intentionally buried property motifs were searched in the artificially derived peptide data containing intentionally buried property motifs. As a result, the expected property motifs were correctly extracted by our algorithm. Second, the peptide data that interact with MHC class II molecules were analyzed as one of the models of biologically active peptides with buried motifs in various lengths. Twofold MHC class II binding peptides were identified with the rule using our method, compared to the existing scoring matrix method. In conclusion, our GP based motif searching approach enabled to obtain knowledge of functional aspects of the peptides without any prior knowledge.