Effect of Proteolytic Bacteria in the Natural Fermentation of Corn to Increase its Nutritive Value

There was no significant difference in % relative nutritive value, lysine or tryptophan levels between natural lactic fermentations of Costa Rican corn meal fermented with tap water of pH 7.2 and 5.3 However, the fermented values were all significantly (P<0.05) higher than nonfermented values. Most of the increase in % relative nutritive value occurred in the first 48 hr. Free essential amino acids increased and the amino acid balance changed during typical fermentations. Proteolytic bacteria decreased after 3 days of the fermentation and declined to a few cells per ml by the 4th day. Proteolysis decreased by the second day of natural lactic fermentation.     

Consequences of nonclassical measurement for the algorithmic description of continuous dynamical systems

Abstract

Continuous dynamical systems intuitively seem capable of more complex behavior than discrete systems. If analyzed in the framework of the traditional theory of computation, a.continuous dynamical system with countably many quasistable states has at least the computational power of a universal Turing machine. Such an analysis assumes, however, the classical notion of measurement. If measurement is viewed nonclassically, a continuous dynamical system cannot, even in principle, exhibit behavior that cannot be simulated by a universal Turing machine.     

Bioavailability of Zinc in Fermented Soybeans

The bioavailability of zinc in soybean meal fermented by lactic acid-producing bacteria (LAPB) and by Rhizopus oligosporus in tempeh fermentation was evaluated with the rat bioassay, using the slope ratio method and log total femur zinc or weight gain versus zinc intake as response parameters. Fermentation significantly increased (P < 0.05) the RBV of zinc from 73.0% in boiled non-fermented soybeans (pH 6.7) to 84.5% in boiled LAPB fermented soybeans. The highest RBV (95.3%) was found in the autoclaved and LAPB fermented product (pH 6.5). Rhizopus oligosporus fermentation resulted in a RBV of 89.0%. Thus, fermentation in the processing of soybeans will improve zinc bioavailability in this food.     

Use of Candida tropicalis ATCC 9968 to Adjust the pH of a Natural Lactic Acid Fermentation of Cornmeal

After 3 days of a natural lactic acid fermentation of whole kernel cornmeal, the pH was 3.78 with a titratable acidity of 0.91% at 32°C (1:4 w/v solids to water). These solids were diluted (1:12 w/v), autocalved at 121°C for 15 min and fermented with C. tropicalis for 7 days at 32°C, bringing the pH to 6.5 and 0.03% acidity. After both fermentations, the % relative nutritive value increased significantly (from 74.09% to 81.22%) and so did riboflavin (from 0.22 to 0.56 mg/100g). Both thiamin and niacin decreased significantly (0.42 to 0.20 mg/100g and 2.13 to 1.94 mg/100g, respectively).     

Fermentation of Corn for Nigerian Agidi

Agidi, a Nigerian food made from corn, was prepared by the traditional Nigerian method and by a modified procedure in which fermented corn was used. The fermented agidi (with or without pH adjustment of the corn) was significantly higher (P < 0.05) in tryptophan and lysine than the nonfermented agidi. Sensory analyses indicated that flavor for the fermented (either pH adjusted or not) had a score greater than average (scale of 1 to 5, with 5 being the highest on the desired scale). However, since total sensory score (total points for color, firmness, acidity and flavor) was less than the traditional agidi, blending of the two is indicated for best acceptance and nutrition.     

STUDIES OF MIXING IN A CONCENTRIC TUBE AIR-LIFT REACTOR CONTAINING XANTHAN GUM BY MEANS OF AN IMPROVED FLOW FOLLOWER

The influence of a pseudoplastic non-Newtonian fluid upon the hydrodynamic performance and mixing parameters of a concentric tube air-lift fermenter has been studied using a range of dilute xanthan gum solutions (0-0.5% weight by volume). Liquid circulation times vary in a complex pattern with increasing gum concentration. At low concentrations, circulation was more; rapid due to drag reduction whilst at the highest concentrations circulation times were increased. The column voidage decreased with increasing gum concentration and bubbly flow in the riser was replaced by slug flow. For all gum concentrations the effective dispersion coefficient for a single passage around the loop was increased relative to tap water. An improved radio-pill flow follower system for hydrodynamic studies is described.