TOTAL AND SOLUBLE DIETARY FIBER VARIATION IN CYAMOPSIS TETRAGONOLOBA (L.) TAUB. (GUAR) GENOTYPES

The endosperm of guar seed is the source of a soluble hydrophilic polysaccharide gum that is used as an emulsifier, thickener and stabilizer in a wide range of foods and is part of the seed total dietary fiber (TDF). This study examined the content and variation in TDF and soluble dietary fiber (SDF) in seeds of guar, Cyamopsis tetragonoloba (L.) Taub., accessions with diverse morphological traits. TDF and SDF, respectively, made up 52–58% (n = 9 accessions) and 26–32% (n = 8 accessions) of seed dry weight. Both TDF and SDF displayed significant genotypic variability. The magnitude of the variability indicates the possibility of improving these traits through plant breeding. Variability of protein, lipid, ash and dry matter content of seed was also observed.     

Fat Concentration Affects Sweetness and Sensory Profiles of Sucrose, Sucralose, and Aspartame

The sensory characteristics of sucralose, aspartame, and sucrose were studied in an unflavored lipid model system varying in fat levels. One study investigated the effects of fat on the potencies (vs. sucrose) of sucralose and aspartame. We also examined absolute changes in all three sweeteners in taste, temporal, and mouthfeel properties at fiied concentrations across a wide fat range. Results indicated a modest decrease in the potencies of sucralose and aspartame across fat concentrations, especially at lower sweetness levels. All sweeteners responded similarly to changes in fat concentration. Independent of fat level, sucralose was perceived more similar to aspartame in onset, bitterness, and aftertaste, than to sucrose.     

Microwave Digestion of Multi-Component Foods for Sodium Analysis by Atomic Absorption Spectrometry

Microwave digestion of a variety of low-sodium dinners was evaluated for determining sodium content. Dinners containing a meat, vegetable and dessert portion were blended, digested with strong acid in the microwave oven, and read by atomic absorption. Sodium values were compared with those obtained by an FDA method. Also, a sodium standard of known concentration was added to some samples, and the recoveries measured for two different amounts added. Reproducibility of microwave digestion was tested on replicates analyzed on the same day, on consecutive days and on consecutive weeks. Of the ten dinner types tested no matrix effects or interferences were noted, and we concluded that microwave digestion is a rapid means of preparing a complex matrix such as a frozen dinner for sodium analysis.     

Isolation of Low-Molecular-Weight Taste Peptides from Vacherin Mont ďOr Cheese

Vacherin cheese samples weie extracted with water and the extracts fractionated by ultrafiltration excluding compounds with a molecular weight less than 1,000. Extract aliquots were fractionated by ligand exchange chromatography on a Sephadex derivative containing N-(2-pyridylmethyl)glycine-groups in Cu²⁺ form, permitting a specific group separation of peptides. Five peptide sub-groups were then chromato-graphed on Aminex A6 and Durrum DC 4 resin. Nine fractions from these separations were characterized by manual gas-phase isofhiocy-anate degradation and HPLC of the amino acid derivatives. Seven peptides could be identified: H-Leu-Pro-OH, H-Val-Pro-OH, H-Phe-Pro-OH, H-Lys-Pro-OH, H-Gly-Pro-Val-Arg-OH, H-Tyr-Pro-OH, and H-Arg-Pro-OH. A partial elucidation of the structure was possible for peptides containing Asp/Pro/Val/Leu, Glu/Leu, and Ala/Pro.     

Polyunsaturated Fatty Acids and Fat in Fish Flesh for Selecting Species for Health Benefits

An awareness of the protective roll of n-3 polyunsaturated fatty acids against development of cardiovascular disease has prompted the promotion of fish consumption. It is assumed that those fish rich in polyunsaturated fat and particularly those having high ratios of n-3 to n-6 polyunsaturated fatty acids would confer the most benefit. The total fat and fatty acid compositional data are reported herein for 41 different species of fish that are mostly found in the coastal waters of the Eastern United States.     

Effect of P2O5 on the Crystallization of Lead Silicate Glasses

The effect of P₂O_S on the devitrification of binary lead silicate glasses containing 64 and 59 mol% PbO was studied. Glasses underwent isothermal crystallization treatments at 400°, 450°, 500°, and 550°C. A polymorph of 3PbO₂SiO₂ was the major product of crystallization for all compositions of glasses. Secondary products of crystallization were found to be a polymorph of PbOSiO₂ in the 59 mol% and a low-temperature polymorph of 2PbOSiO₂ in the 64 mol% PbO glasses. Dominant mode of crystallization in both binary glasses was surface devitrification at all temperatures studied. Addition of P₂O₅ promoted internal crystallization in the form of spherulites. 400°C was found to be the most effective temperature for nucleating spherulitic growth. Crystallization at 400°C led to high concentrations of spherulites in all glasses containing at least 0.5 mol% P₂O₅. Concentrations of 0.5 mol% P₂O₅ were needed to produce detectable levels of spherulitic nucleation at r<400°C.     

A comparison between ceramic and polymeric membrane systems for casein concentrate manufacture

Skim milk microfiltration (MF) is a well established dairy processing operation to remove whey proteins. This is classically completed using ceramic membranes under the uniform transmembrane pressure (UTMP) concept. However, there is a growing interest in the use of spiral wound polymeric membranes for this purpose due to their lower capital cost. In this work we show that polymeric and ceramic membranes provide comparable performance during skim milk MF when operated at comparable levels of transmembrane pressure (TMP), shear stress and temperature. Operation is strongly affected by both TMP and temperature but is less affected by crossflow velocity under the conditions utilised here. However, while polymeric membranes offer similar performance, it will be operationally difficult to retain the necessarily low TMP at the industrial scale, due to the lack of a comparable UTMP configuration.     

Effect of long‐chain inulin on the texture profile and survival of Lactobacillus paracasei ssp. paracasei in set yoghurts during refrigerated storage

The effects of adding inulin at 20 g/L as a fat replacer and probiotic bacteria on the physicochemical and textural characteristics of yoghurt were studied. The ability of long‐chain inulin to improve the probiotic (Lactobacillus paracasei ssp. paracasei) bacteria viability in yoghurt was investigated. The addition of inulin made the texture (firmness, cohesiveness, adhesiveness and gumminess) of skimmed yoghurt similar to that of whole yoghurt, demonstrating the role of inulin as a fat replacer. However inulin increased syneresis and did not influence the viability of probiotic bacteria in the yoghurts. The addition of probiotic bacteria in yoghurts improved syneresis and increased firmness and gumminess.     

MICROFILTRATION OF RED BERRY JUICE WITH THREAD FILTERS: EFFECTS OF TEMPERATURE, FLOW AND FILTER PORE SIZE

A series of experiments was conducted to demonstrate the applicability of a new Filtomat® thread filtration principle for microfiltration of semiprocessed blackcurrant juice and cherry juice. The effect of juice temperature (3–20C), flow (20–80 L/h), and filter pore size (3–10 μm) on the transmembrane pressure, juice turbidity, protein, sugar, and total phenols levels was evaluated in a lab scale microfiltration unit employing statistically designed factorial experiments. Thread microfiltration reduced significantly the turbidity of both juices. For blackcurrant juice, in all experiments, the turbidity was immediately reduced to the level required for finished juice without compromising either the protein, the sugar or the phenols content. High flow rates increased the turbidity in blackcurrant juice, but did not affect cherry juice quality. Filtomat® thread microfiltration therefore appears suitable as a novel technology for berry juice processing, especially for blackcurrant juice filtration.