Influence of Processing on Physical Form of Beans and on Intestinal Fermentation

Three red kidney bean-containing diets and one fiber-free diet were fed to five Yucatan miniature swine to evaluate the influence of the physical form of a high-fiber food on fermentation in the gut. Beans were processed by three techniques prior to cooking: the conventional soak and autoclave procedure, a wet-milling technique, and a dry-milling technique. Breath gases were collected from the animals and the concentrations of hydrogen and methane were determined to assess intestinal fermentation. Even though differences among the three bean preparations could be detected microscopically, these differences were not reflected in the physiological measurements since the extent of fermentation was similar for the three bean diets.     

BASIS OF STABILITY OF AMINE SALTS OF LINOLEIC ACID

SUMMARY— The mechanism and generality of the known stabilization against autoxidation conferred on linoleic acid by certain basic amino acids, such as lysine and arginine, was investigated. Basic amino acids were the only class of compounds found to confer the effect. However, the smallest basic amino acid, 2,3-diaminopropionic acid, was not effective, nor was αβω-diaminc acid, 3,6-diaminohexanoic acid, although a simple isomer of lysine. The stabilization was observed only in the solid phase. Inclusion of sodium chloride in the solid matrix was deleterious to the effect. A large number of physical and chemical observations were made and correlated but it has not been possible to draw detailed conclusions about the mechanism of stabilization, nor can a detailed structure of the stabilized complex be suggested. The cause of the phenomenon appears to be closely associated with the physical arrangement of the ions in the crystal lattice.     

AREA- AND PERIMETER-DEPENDENT PROPERTIES AND FAILURE OF MATURE-GREEN AND RED-RIPE TOMATO PERICARP TISSUE

The influence of tomato fruit ripeness on area- and perimeter-dependent properties and dominant failure mechanisms of pericarp tissue were investigated. Tissue discs from mature-green and red-ripe fruit were punctured with a flat-ended cylindrical probe and compressed with a flat plate at a constant rate of deformation. Approximately linear force-deformation curves were obtained to tissue failure by both puncture and flat plate compression, interrupted by a region of pseudoplastic deformation at a relatively low initial bioyield force. Based on estimated area- and perimeter-dependent coefficients and firmness (force/deformation) values, initial bioyielding of tissue appeared to be associated with an abrupt increase in cell-to-cell compaction. Puncture of mature-green tissue led to premature failure induced by shearing or rupture of tissue at the probe perimeter. The contribution to puncture of perimeter-dependent or shear-associated forces and a putative "zone of influence" increased markedly with ripening, while the contribution of area-dependent or compression associated forces generally decreased. A concomitant decrease in failure force and firmness with ripening reflected a general loss of both tissue compression and shear strengths. These results suggested that the dominant mode of tissue failure changed with ripening, from cell relaxation and rupture to cell debonding. The data obtained in this study emphasize the need to exercise caution in the interpretation of force-deformation parameters derived from puncture tests alone.     

Specific Permeability of Porous Compacts as Described by a Capillary Model

The specific liquid permeabilities of a wide variety of phosphatebonded, porous alumina compacts prepared from alumina powders of differing size distribution, and ranging in porosity from 32 to 50 vol%, were not described well by the Carmen-Kozeny model but were described by a capillary model based on mean entry pore radius. The specific permeability varied directly with the square of the mean entry pore radius determined by mercury intrusion. The compacts containing the lowest phosphate bond phase obeyed Poiseuille's law.     

CHILLING INJURY. A REVIEW OF QUALITY ASPECTS

The various quality aspects of chilling injury (CI) serve as the focus of this review in which symptoms, occurrence and its alleviation are discussed. CI is a term used to describe the physiological damage that occurs in many plants and plant products, particularly those of tropical and subtropical origin, as a result of their exposure to low but nonfreezing temperatures. The substantial economic consequences of CI have provided the impetus for studying/developing effective means of alleviating symptoms which manifest this disorder. A diversity in plant responses to low temperature stress exists, including alterations in ethylene biosynthesis, increased respiration rates, cessation of protoplasmic streaming, increased solute leakage, and uncoupling of oxidative phosphorylation. These various responses ultimately give rise to an array of visual symptoms (e.g., surface pitting, water rot, poor color development, general loss of structural integrity) which can render severe losses in product quality both pre- and postharvest. A number of different methods are available by which to alleviate symptom development, including manipulation of storage conditions (e.g., temperature cycling, hypobaric and modified atmosphere storage), exogenous chemical treatments (e.g., application of phospholipids, antioxidants, calcium) and genetic modification of chill sensitive species. These are discussed with respect to their effectiveness and possible control mechanisms.     

Growth of Beryllia Single Crystals

Single crystals of beryllia have been grown by two methods. One method exploits the high-temperature reversible reaction BeO + H₂O.Be(OH)₂. The other is a flux method, in which BeO is dissolved and precipitated as single crystals in a lithium molybdate flux. Characteristics and remaining problems of the two methods are discussed, and the crystals produced are described.     

Lipid-Soluble Vitamins in Blood and Liver of Rats Fed a Diet Containing Hard Red Spring Wheat Bran

Semipurified diets containing either 0 or 20% wheat bran were fed ad libitum to male Sprague-Dawley rats for 9 wk. Wheat bran consumption had no effect on vitamin A or E levels in plasma, leukocytes, or liver, nor on vitamin E levels in erythrocytes of these rats after 9 wk of feeding. However, during the study period, values showed transient declines. Both vitamins showed similar declines in leukocytes and livers of the bran-fed rats. Erythrocyte vitamin E levels also were influenced by the wheat bran diet but no erythrocyte vitamin A could be detected. Thus, rats adapt to diets containing high levels of wheat brans, perhaps by metabolic or gastrointestinal modifications.     

Fluorescence Intensity Indicates Bean Hardening

Fluorescence microscopy was used to measure the intensity of fluorescent emanation from the cut surface of uncooked bean cotyledons. This parameter correlated significantly with the hardness of soaked cooked beans determined by either compression force of whole beans or the probe force of cotyledons only. This relationship existed whether hardness resulted from varietal differences or elevated storage conditions. Similarly, a significant correlation was found between the fluorescence intensity of isolated cell wall material and bean hardness. These results led to the conclusion that the increase in fluorescence intensity in hard beans may have been due to the accumulation of phenolic compounds within the cell wall and that the procedure developed had potential as a quicker and simpler way to determine bean hardness.