CHANGES IN PROTEIN COMPOSITION DURING STRAWBERRY (Fragaria × ananassa Duch.) FRUIT RIPENING1

The changes in strawberry native proteins and polypeptides during ripening were studied. Analysis of protein extracts by nondenaturing electrophoresis showed the presence of a protein species only in the ‘25% Red’ and later ripening stage. This 40 kD polypeptide was hardly detected in ‘Large green’ and ‘White’ fruit extracts. The polypeptide profile, obtained with SDS-PAGE, also changed during ripening. While most polypeptides were found in all ripening stages, the distribution of some of them varied during ripening. Protein synthesis (measured by ³⁵ S-methionine labelling) in strawberry was mainly directed towards the regeneration of previously existing proteins. As ripening proceeded, the synthesis of 67 and 63 kD polypeptides increased, while those of 82, 56 and 25 kD decreased. Three very-abundant polypeptides (36, 24 and 23 kD) were located in the achenes and were not labelled in any ripening stage.     

VARIATION AND RELATIONSHIPS AMONG SOME NUTRITIONAL TRAITS IN SICILIAN GENOTYPES OF CHICKPEA (CICER ARIETINUM L.)

The chemical composition of several chickpeas originating from Sicily, compared with the International Center for Agricultural Research in the Dry Areas genotype “ILC 484” and the Italian cultivar “Calia,” was determined. A large variability was ascertained for crude fiber (coefficient of variation [CV] = 29.3%), calcium (CV = 39.3%) and tannins (CV = 120.0%). The genotype statistically affected all nutrient characteristics assessed, whose mean values were: (1) 100‐seed weight 34.0 ± 3.3 g; (2) crude fiber 2.88 ± 0.8 g/100 g; (3) fat 6.0 ± 0.9 g/100 g; (4) total carbohydrates 62.0 ± 1.4 g/100 g; (5) ash 2.64 ± 0.2 g/100 g; (6) iron 4.50 ± 0.3 mg/100 g; (7) calcium 109.6 ± 43.1 mg/100 g; (8) magnesium 189.4 ± 18.5 mg/100 g; (9) potassium 1318.7 ± 95.6 mg/100 g; and (10) tannins 0.90 ± 1.1 g/100 g. An average energy value of 379.8 ± 6.2 kcal/100 g was computed. The wide variability ascertained for some chemical attributes such as crude fiber, tannins and Ca content, and interesting correlations observed among characteristics, such as the negative correlation between Fe and tannins or fiber, or the positive correlation between ash and Fe, suggest the possibility of identifying genotypes to be used in breeding programs for the improvement of chickpea quality in Sicily.     

Interaction of Antibiotics and Water Activity on Streptococcus thermophilus and Lactobacillus bulgaricus

Acid production was determined in cultures of Streptococcus thermophilus and Lactobacillus bulgaricus in the presence of penicillin and gentamycin in milks with water activity adjusted between 0. 992 and 0.943 by adding glycerol, glucose or sucrose. Resistance of S. thermophilus A TCC 19258 and CRL 410 to penicillin increased when a_w was lowered with glycerol from 0.992 to 0.995, and from 0.992 to 0.985 in L. bulgaricus ATCC 11842. Susceptibility to gentamycin increased in both species with reduction of a_w. Susceptibility of S. thermophilus CRL 410 to penicillin increased in most cases when a_w was adjusted with glucose, while acid production at a a_w of 0.985 was always higher than that of the controls (a_w 0.992) when sucrose was used. With L. bulgaricus CRL 420, lower acid production was observed at all penicillin concentrations, whether glucose or sucrose was used as the humectant.     

Mineral Loss in Cowpeas [Vigna unguiculata (L.) Walp] by Pressure Heating in Water

White Acre cowpeas of four maturity levels were heated in water at 35 kPa for 0–40 min. As the cowpeas increased in maturity, Zn, Cu, Mn, Mg, and K increased, Fe decreased and Ca did not change. All minerals analyzed decreased with heating: Cu, Ca and Mg (p < 0.001), Zn, Fe and K (p <0.01) and Mn (P<0.05). Minerals leached from the cowpeas at different magnitudes and rates. For example, K lowered 70–80% within 10 min; others lowered 20% or less. Loss of minerals across maturity stages was not uniform. This method reduced loss of certain minerals when compared to published values for the boiling water method.