Robert L. Ory

Association of lipase activity with the spherosomes of Ricinus communis

Abstract The fatty layer obtained after centrifuging a macerate of ungerminated castor beans, Ricinus communis , contains an active lipase. The fatty layer has been examined by a combination of biochemical and electron microscopic techniques before and after periods of active lipolysis with Pb ++ in the reaction mixture. The results confirm the presence of spherosomes, the fat storage organelles of the cells, concentrated in the fatty layer. Lipase activity is localized in the spherosomes derived from endosperm tissue of ungerminated seeds.

Acid lipase of the castor bean

The acid lipase of the castor bean is present in the dormant seed. It is extracted from the fat pad obtained by centrifuging a macerate of the seed in pH 7.0 buffer containing cysteine and ethylene diaminetetraacetic acid. The pH optimum of the enzyme is 4.2; it is rather heat-stable, and is inhibited by mercurials and sulfhydryl reagents. Maximum hydrolysis of saturated triglycerides occurs with fatty acids of chain length C4 to C8; unsaturated C18 triglycerides are hydrolyzed at a slightly lower rate.This lipase is a three-component system consisting of the apoenzyme, a lipid cofactor (a cyclic tetramer of ricinoleic acid), and a protein activator (a small, heat-stable glycoprotein which appears to be related to some of the castor allergens). Maximum lipolysis requires all three components. Lipase activity is associated with the spherosomes, the subcellular site of oil storage in the endosperm.

Comparison of methods for determining peroxidation in processed whole peanut products

Oxidation of fatty acids in peanut butter produces peroxides and changes in the conjugated diene contents. Two of the most widely used methods for measuring these oxidative effects, peroxide value and the spectrophotometric assay of conjugated diene hydroperoxides, were compared in determinations of shelf-life stability of peanut butters during short and long term storage. Results by the conjugated diene hydroperoxides method correlated with those by the peroxide value method over 4 and 12 week storage periods. The conjugated diene hydroperoxides method requires smaller samples and is quicker, more accurate, and simpler than the peroxide value method, nor does it require additional reagents nor depend upon a chemical reaction or color development.

Changes in lipid composition of germinating barley embryo

Barley seeds,Hordeum vulgare, var. Kenia, were dissected before and after 5 days of germination, to distinguish between the scutellum, the coleoptile half of the embryo and the coleorhiza half of the embryo. Total lipids were extracted from each fraction and analyzed by thin layer chromatography and gas liquid chromatography. In tissues from the coleoptile and coleorhiza halves of the embryo there was a concurrent disappearance of triglycerides with a marked increase of esterified sterols and esterified sterol glucosides. In the scutellum there was also a change in triglycerides, but the variations in contents of esterified sterols and esterified sterol glucosides were much smaller. Mono- and digalactolipids were virtually absent from embryonic tissue. The amounts of linoleic and linolenic acids in esterified sterol glucosides were increased after 5 days of germination in all the embryonic tissues, especially in the coleoptile half. In sterol esters, linoleic acid comprised nearly half of the total fatty acids, and the desaturation after 5 days of germination was much less pronounced.

Peanut proteins as food supplements: A compositional study of selected Virginia and Spanish peanuts

Three peanut cultivars (Virginia, red-skinned, and white-skinned Spanish) were analyzed and compared as potential protein supplements for food uses. The seeds were solvent-extracted in the laboratory to yield defatted flours with 9–10% nitrogen contents. Protein isolates were prepared from the flours by subsequent extraction with dilute salt solutions buffered at pH 7.0. Various parameters were compared, such as total protein contents, soluble proteins, amino acid compositions of flours and protein isolates, free amino acids and free sugars of defatted flours, and certain trace minerals in flours and soluble proteins. The application of these results to the selection of certain types of peanuts for potential uses as protein supplements in food products is discussed.

Ureide metabolism in castor beans. Evidence for a particle-bound allantoinase

Abstract Allantoinase in germinating castor beans has been detected in a solubilized preparation. Unlike the enzyme reported in legumes this one is absent in dormant seed. It appears to be associated with some particulate material and was freed from its bound form with sodium desoxycholate. It has a pH optimum of 7·5–7·6 and a K m of 13·8 mM (Lineweaver-Burk).

Electrophoretic characterization of six selected enzymes of peanut cultivars

Abstract The isozyme patterns (both anodic and cathodic) of esterase, catalase, leucine aminopeptidase, acid phosphatase, alcohol dehydrogenase and INT oxidase in individual seeds from several peanut cultivars ( Arachis hypogaea ) were characterized by polyacrylamide and starch gel electrophoresis in relation to the stages of seed development, maturity, and germination, geographic areas where grown and phylogenetic relationship. Of the six enzymes examined, only esterase contained cathodic isozymes, of which the patterns served to distinguish between the Spanish and the Virginia-type peanuts. Anodic esterase and acid phosphatase zymograms of early developing and germinating peanuts could be distinguished from those of predormant and mature seeds and the latter showed much intravarietal variation which was consistent among cultivars and the geographic areas where grown. Anodic isozymes of catalase, leucine aminopeptidase, alcohol dehydrogenase and INT oxidase were synthesized very early in peanut development and remained constant through maturity and to at least 24 hr germination; they were consistent within and between peanut cultivars and they were not influenced by the environmental conditions of the areas where the peanuts were grown. The consistency of the isozyme patterns within and between cultivars supports the suggestion that plant breeding programs used to develop superior cultivars have produced genetic uniformity in peanuts.

Storage Quality of Brown Rice as Affected by Packaging with and without Carbon Dioxide

Shelled brown rice (100 g/bag) was packed in regular plastic bags in air, in laminated film (nylon-EVA) bags in air, and in laminated bags plus CO2. Samples of each were stored in the dark at 4 C and at 24 C, and samples were removed after 1, 3, 5 and 7 months for analysis of odor changes, free fatty acids, total microbial counts, total lipolytic fungi and bacteria, lipid peroxides and gas chromatographic volatiles profiles. Brown rice in laminated bags plus CO2 was more stable under refrigerated conditions than at ambient temperatures. However, at 24-C storage there was no consistent significant decrease in free fatty acids, lipid peroxides and volatile compounds in these bags compared to the other types of packing. Laminated bags seem to have had an adverse effect on total microbial populations at both 4 and 24 C. Selection of either type of package for brown rice would be governed by end use, storage time and conditions.

Localization of an acid proteinase in hempseed

Abstract An acid proteinase was detected in a solubilized preparation of dormant hempseed. It has an optimum pH of 3·2 with hemoglobin as substrate, and 4·3 with its natural substrate, edestin. The enzyme is temperature sensitive, the optimal temperature being 53°. Aleurone grains (protein bodies) are the principal subcellular site for the acid proteinase.

Rapid enzymatic method for partial hydolysis of oilseed proteins for food uses.

Abstract and SummaryPlant enzymes were used to obtain partially hy-drolyzed oilseed proteins. Hydrolysis of oilseed pro-teins under different conditions of type of enzyme, enzyme concentration, temperature, and reaction time was investigated to develop optimum conditions. Pilot plant-produced defatted peanut flour treated with a 0.5% aqueous solution of papain at 45 C yielded a product that had 50% more soluble protein but with no increase in the microbial count of the original flour. Hydrolysis reached equilibrium in 10-15 min. Because of the mild reaction conditions of the method, enzymatic hydrolysis offers major advan-tages over nonenzymatic methods for modifying plant proteins for incorporation in specialty food products.