Betty A. Lewis

A simple method for estimation of neutral detergent-soluble fibre

A method was developed to estimate the neutral detergent-soluble fibre (NDSF) content of feeds. Citrus pulp, sugar beet pulp, soybean hulls, separated leaves and stems from mature and immature alfalfa, red clover, reed canarygrass and timothy were analysed. Half-gram samples were stirred at room temperature for 4 h with 100 ml of 90:10 (v/v) ethanol/water to extract low molecular weight substances, crude protein (CP) and ash to produce ethanol-insoluble residues (EIR). Samples were refluxed for 1 h with neutral detergent solution and heat stable α-amylase to extract low molecular weight substances, NDSF, starch, CP and ash to produce neutral detergent residues (NDF). The EIR and NDF were analysed for organic matter (OM; EIROM; NDFOM) and CP (EIRCP; NDFCP), and EIR was analysed for starch. Values were expressed as proportions of the original sample dry matter. The NDSF was calculated as the difference in OM mass between EIR and NDF after correction for CP and starch by the equation: EIROM-NDFOM-EIRCP+NDFCP-EIR starch. Extractions with 90:10 (v/v) ethanol/water gave a higher yield of EIR and NDSF than did 80: 20 (v/v) ethanol/water. The method gave good precision and is convenient for assessing NDSF content of feeds.

Phloem transport of antirrhinoside, an iridoid glycoside, inAsarina scandens (Scrophulariaceae)

Iridoid glycosides, terpene-derived compounds found in many plant families, protect the plant against generalist and nonadapted specialist insect herbivores, fungi, and bacteria. Antirrhinoside, a common iridoid glycoside in the tribe Antirrhineae (Scrophulariaceae), was rapidly labeled when mature leaves ofAsarina scandens were exposed to14CO2. Antirrhinoside was translocated in the phloem along with sucrose. Radiolabeled antirrhinoside appeared in the petiole of the labeled leaf within 20 min of the beginning of the labeling period. Antirrhinoside was also found in phloem sap obtained by the EDTA method.

Molecular structure of fagopyritol A1 (O-α-d-galactopyranosyl-(1→3)-d-chiro-inositol) by NMR

The molecular structure of fagopyritol A1, a novel galactopyranosyl cyclitol from buckwheat seeds, was determined to be O-alpha-D-galactopyranosyl-(1 --> 3)-D-chiro-inositol by 1H and 13C NMR. Fagopyritol A1 is a positional isomer of fagopyritol B1 (O-alpha-D-galactopyranosyl-(1 --> 2)-D-chiro-inositol), representing a different series of fagopyritol oligomers. Trimethylsilyl derivatives of both compounds have similar mass spectra, but each may be identified by different abundance ratios of fragments with m/z 305/318 and 318/319.

Evaluation of starch analysis methods for feed samples

The objectives of this work were to evaluate the efficacies of commercial starch analyses and of starch analysis extraction and gelatinisation procedures. In Study 1, accuracy and specificity of commercially available starch analyses were evaluated with six co-operating laboratories (five commercial, one university). Results from 11 test samples showed three laboratories with recoveries of purified starch of 92 g kg−1 or less. Three and four laboratories had inflated values when samples contained glucose or sucrose, respectively. Analyses appeared to have good specificity for glucose. Incompleteness of starch detection and interference by non-starch carbohydrates can affect commercially available analyses. In Study 2, extraction with 80:20 ethanol/water (v/v; 80EtOH) or 90:10 ethanol/water (v/v; 90EtOH) to remove low-molecular-weight carbohydrates, and gelatinisation with heat, alkali (KOH), 6 M urea or 8 M urea were evaluated. Extraction with 80EtOH or 90EtOH reduced interference from non-starch carbohydrates. Gelatinisation with heat was adequate for good recoveries of starch glucose for both control (non-extracted) and 80EtOH-extracted samples; gelatinisation with alkali was required for 90EtOH-extracted samples. Recoveries of pure starch samples were greatest with no extraction and heat gelatinisation. 80EtOH extraction with heat gelatinisation appears to be an adequate preparation method when removal of low-molecular-weight carbohydrates is desired. © 2000 Society of Chemical Industry

Laminaranase activity in the crystalline style of the surf clam (Spissula solidissima)

Isolierung und Charakterisierung eines Enzyms ausSpissula solidissima, welches die Fähigkeit besitzt, gewisse Polysaccharide spezifisch zu spalten.

Phenolics, Sugars, Antimicrobial and Free-Radical-Scavenging Activities of Melicoccus bijugatus Jacq. Fruits from the Dominican Republic and Florida

Edible fruits of the native South American tree Melicoccus bijugatus Jacq. are consumed fresh or in traditional food, drink and medicinal preparations. Some therapeutic effects of these fruits may be due to phenolics and sugars. Aqueous acetone, methanol or ethanol tissue extracts of different cultivars or collections of M. bijugatus fruits from the Dominican Republic and Florida were analyzed for total phenolics and free radical scavenging activity by UV-vis spectroscopy, sugars by gas chromatography, and antimicrobial activity by the disc diffusion assay. Total phenolics and free radical scavenging activities ranked: seed coat > embryo > pulp extracts. Montgomery cultivar fruits had the highest total phenolics. For sugars: pulp > embryo and highest in Punta Cana fruit pulp. In all extracts: sucrose > glucose and fructose. Glucose:fructose ratios were 1:1 (pulp) and 0.2:1 (embryo). Pulp extracts had dose-response antibacterial activity and pulp and embryo extracts had antifungal activity against one yeast species. Phenolics and sugars were confirmed with thin-layer chromatography and nuclear magnetic resonance. Sugar-free pulp fractions containing phenolics had slightly more antimicrobial activity than H2O-soluble pulp fractions with sugars. Results indicate M. bijugatus fruits contain phenolics, sugars and other H2O-soluble compounds consistent with therapeutic uses.

Analysis of Foodstuffs for Dietary Fiber by the Urea Enzymatic Dialysis Method

Total dietary fiber (TDF) values for cereal grains, fruits, vegetables, processed foods, and purified or semi-purified dietary fiber products were determined by a new method using 8M urea and enzymes (urea enzymatic dialysis, UED, method). The results are compared with the official AOAC procedure. Soluble and insoluble dietary fiber were determined for several of these foodstuffs and compared with the NDF values. Crude protein and ash contamination was usually lower with the UED method compared with the AOAC method, particularly for samples that formed gels during ethanol precipitation. Urea and the heat stable amylase were effective in removing starch even at relatively low temperatures of the assay (50 degrees C). The new assay is relatively economical in use of equipment, enzymes, and reagents. Studies are currently in progress to minimize the assay time for the UED method while further improving its flexibility and robustness. The results of the studies will be discussed.