Effect of soybean substitution on some physical,compositional and sensory properties of<Emphasis Type="Italic"> kokoro</Emphasis> (a local maize snack)

Kokoro was prepared from maize–soybean flour mixtures in ratios of 100:0, 90:10, 80:20, 70:30, 60:40 and 50:50. The physical, compositional, and sensory characteristics of kokoro were evaluated. Protein and fat contents increased, while carbohydrate content decreased as the soy flour proportion of the flour mixture used in the kokoro was increased. The bulk density and water-holding capacity increased with increasing proportion of soybean flour, while the swelling capacity was found to decrease. High soy-substitution significantly reduced the sensory acceptance of kokoro. Sensory evaluation indicated that maize:soybean flour mixture ratios of 100:0 and 90:0 were the most acceptable to the panellists.     

Sensory,microbiological, and chemical spoilage of cultured common sea bass (<Emphasis Type="Italic"> Dicentrarchus labrax</Emphasis>) stored in ice: a seasonal differentiation

Common sea bass ( Dicentrarchus labrax) of a Greek cage-culture origin, sampled in December and July, were stored in ice, and their sensory, microbiological and chemical spoilage patterns were studied as well as their seasonal differentiation. The sensory storage life was determined at 15 days of ice storage. The microbial population in the muscle reached levels of 10⁵ at the acceptability limit. The ATP breakdown pattern showed a quick depletion of inosine-monophosphate (IMP) in the first 8–9 days of ice storage and slower depletion thereafter. Inosine (INO) and hypoxanthine (Hx) were formed at significant quantities. TVBN and TBA, as indicators of protein breakdown and lipid oxidation, respectively, showed low and delayed increase. A seasonal effect was observed with summer fish showing higher rates of K-value increase during early spoilage, while winter fish showed higher K-values, microbial populations and TVBN at late spoilage stages.     

Effect of an additionally introduced degQ gene on di-d-fructofuranosyl 2,6′:2′,6 anhydride (DFA IV) production by recombinant Bacillus subtilis in a single culture production system

Di-d-fructofuranosyl 2,6′:2′,6 anhydride (DFA IV) was produced directly from sucrose using a single culture of recombinant Bacillus subtilis 168 carrying the levan fructotransferase (lft) gene. In this study, three plasmids carrying the degQ36 gene, which is a degQ allele of B. subtilis (degQ36) with a degQ36 mutation on its promoter, were constructed to overproduce intact DegQ in B. subtilis 168. The transformant B. subtilis/pHT-D36 (with the degQ36 gene) consumed sucrose and produced levan at a higher rate than B. subtilis/pHT43 (without the degQ36 gene). The transformant B. subtilis/pLFT-GD36, carrying the lft and degQ36 genes, also consumed sucrose at a higher rate and produced more DFA IV than B. subtilis/pLFT-G, carrying the lft but without the degQ36 gene. B. subtilis/pLFT-GD36 produced 43.5 g/l of DFA IV and consumed 240 g/l of sucrose (96% of added sucrose) by 72 h of cultivation, whereas B. subtilis/pLFT-G produced 23.4 g/l of DFA IV with 76.9 g/l of sucrose still remaining in the system. Sucrose-inducible expression vectors were also constructed, which made it possible to produce DFA IV without IPTG induction. Using these vectors, sucrose consumption rates were enhanced and DFA IV production was increased upon introduction of the degQ36 gene. From these results, it can be concluded that the additionally introduced regulatory gene, degQ, was able to stimulate sucrose conversion to levan, and therefore increased DFA IV production in this system.