Processing Factors Influencing Splitting and Other Quality Characteristics of Canned Kidney Beans

Single factor changes from a standard canning process indicated that significant reductions in splitting resulted from higher soak Ca concentrations, higher soak temperatures, higher brine Ca concentrations, and shorter cooking times. Splitting in canned kidney beans was markedly reduced by soaking beans before cooking at temperatures of 66–71°C in solutions containing 150–350 ppm CaCl₂. Treatments giving lower gain in weight during soaking led to less splitting. Lower splitting was associated with lower drained weight and firmer cooked beans.     

Variation of Vitamin Concentration and Retention in Canned Snap Beans from Three Processing Plants During Two Years

A statistical evaluation of vitamin status during canning was obtained from samplings of raw, blanched and canned snap beans. With the exception of folic acid retention, it was not possible to distinguish the separate plants. This leads to the expectation that the season averages of vitamins from processing plants obtaining material from the same area would be similar. Retention percentages were lower for thiamin, folic acid and B₆ than for ascorbic, which was lower than for carotene. Raw material was a source of variation. Average concentrations in drained canned beans, dry weight basis were: ascorbic acid, 116 mg/100g; carotene, 22 μg/g; thiamin, 3.4 μg; B₆, 5.3 μg/g; and folic acid, 7.3 μg/g.     

A Collaborative Study to Develop a Standardized Food Protein Solubility Procedure

A colaborative study was conducted to develop a rapid, simple and reliable procedure for determining the solubility of food protein products, e.g., spray-dried whey protein concentrate, sodium caseinate, egg white protein and soy protein isolate. The procedure was developed by modifying the nitrogen solubility index (NSI) procedure. Protein content and soluble protein were determined by micro-Kjeldahl or biuret procedures with standard deviations of 0.83-4.12 for all proteins except caseinate which had a value of 13.95. Although the biuret and micro-Kjeldahl procedures generally provided comparable accuracy and precision for protein content and solubility of certain proteins, the biuret procedure exhibited considerable error and variability for other proteins.     

Effects of Salts Added After Cooking on the Texture of Canned Snap Beans

Soaking bean pods in NaCl solutions caused decreases in firmness and increases in Ca⁺⁺ solubilization as the NaCl concentration increased. CaCl₂ soak solutions increased firmness of pods previously softened by soaking in KCl solutions. Chlorides of Na⁺, K⁺, Li⁺, NH₄⁺, and Mg⁺⁺, and Na acetate caused softening. LiCl caused the most softening, while MgCl₂ caused the greatest solubilization of Ca⁺⁺. Salt-induced softening was accompanied by Ca⁺⁺ displacement. Firmness of salt-softened pods was further decreased by subsequent removal of the salt, indicating an electrostatic component as a minor factor in pod texture.     

Effects of Post-Harvest Handling and Processing on Vitamin Contents of Peas

Vitamin contents of peas were measured at various stages of raw product handling, during 1976–1979 seasons, on different cultivars, on different sizes of peas, at various stages of processing, and at different processing plants. Some cultivar differences were shown in ascorbic acid, carotene, and folic acid, and different sizes of peas contained significantly different amounts of ascorbic acid, carotene, and thiamin contents. Profound effects were observed during blanching and thermal processing of peas. Ascorbic acid, thiamin, vitamin B₆, and niacin contents of canned peas were significantly (95% level) lower than those of fresh peas. Also some significant differences in vitamin contents of canned peas among different processing plants were observed.     

Effects of Salts and pH on Heating-Related softening of Snap Beans

The effects of salts and pH on softening during cooking were tested by modifying solutions in which pods were heated. Ca displacement was minimized by soaking heated pods in 0.2M CaCl₂ before measuring firmness. Softening was increased independently by the presence of salts and when pH was raised from 5.2 to 6.2. Cations decreased firmness in the order Li > Na = K > NH4 and Ca > Mg. Anions decreased the firmness in the order SO₄ > acetate > CI > NO₃. Firmness differences persisted at long heating times. The results support the hypothesis that pectin β-elimination was the principal softening reaction.     

Two Distinct Pectin Fractions from Senescent Idared Apples Extracted Using Nondegradative Methods

After removal of water-soluble pectin from senescent Idared apples, an additional sizable pectin fraction could be extracted using Na₂EDTA under nondegradative conditions. This chelator-soluble fraction did not appear to owe its insolubility in the cell wall solely to molecular charge. The galacturonic acid-rich polymers of chelator-soluble pectin were notably lower in arabinose galactose and rhamnose residues than those of water-soluble pectin.