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The true resistant starch (RS) content of recrystallissed amylose (RCA) in the small intestine was measured using ileorectostomized rats to determine physiologic functions of RCA. The estimated in vivo resistant starch content of RCA was the same as the value obtained from the in vitro enzymatic RS determination.

The effect of heat treatments on food products related to soybean curd contaminated with Bacillus cereus spores was investigated for the purpose of preventing food-poisoning outbreaks by B. cereus. In the case of B. cereus strains isolated from foods, heating foods inoculated with the spores for 20 min at 70 degrees C, 5 min at 75 degrees C, 2 min at 100 degrees C, or 10 sec with a microwave oven plus reheating after standing for 2 hr at 25 degrees C reduced the number of surviving cells within the foods to less than one-hundredth. In the case of a heat-resistant strain isolated from a food poisoning outbreak, heating for 20 min at 70 degrees C plus reheating after standing for 1.5-2 hr at 35 degrees C, heating for 10 min at 75 degrees C plus reheating after standing for 1.5-2 hr at 35 degrees C, or heating for 2 min at 100 degrees C plus reheating after standing for 4 hr at 25 degrees C was effective. There was not much difference between the flavor components in foods with and without heat treatment at 70 degrees C, as analyzed by gas chromatography-mass spectrometry. These results indicate that these heat treatments are available to control B. cereus spores, without affecting the sensory quality of the foods.

An enrichment procedure and a polymerase chain reaction (PCR) method for the detection of injured Escherichia coli O157 in foods were examined. Freeze-injured E. coli O157 inoculated in boiled spaghetti could be detected in 6-h culture within 12 h by the PCR method. Cells injured by heating in boiled spaghetti and cells injured by chlorine treatment in raw lettuce and carrot did not grow sufficiently to be detected in 6-h culture but were detected in 18-h culture using selective agar media. The injured cells could be also detected in 18-h culture within 24 h by the PCR method. Enrichment at 42 degrees C in trypticase soy broth (TSB) was more effective than that at 42 degrees C in modified EC broth with novobiocin. These results indicated that the usage of enrichment in TSB for 18 h at 42 degrees C in combination with the PCR method is suitable for screening for E. coli O157 in boiled or chlorinated foods, even if the O157 cells are injured.

Angiotensin I-converting enzyme (ACE) inhibitory peptide was isolated from wheat gliadin hydrolysate prepared with acid protease. Consecutive purification methods were used for peptide isolation including ion-exchange chromatography, size-exclusion chromatography, and reverse-phase high-performance liquid chromatography. The amino acid sequence of this peptide was identified as Ile-Ala-Pro, and the ACE inhibitory activity (IC50 value) was 2.7 microM. The hypotensive activity of Ile-Ala-Pro on spontaneously hypertensive rats was investigated. This peptide inhibited the hypertensive activity of angiotensin I with intravenous injection, and decreased the blood pressure significantly with intraperitoneal administration.