水豆豉和纳豆的理化特性及抗突变效果的比较

水豆豉和纳豆都是传统的细菌型发酵大豆食品。本文采用理化方法对两者品质进行比较,研究表明,两者所含的一般成分含量接近;纳豆的氨基态氮、氨态氮含量高于水豆豉,γ-谷氨酰转肽酶活性低于水豆豉;在感官评价上水豆豉优于纳豆。采用Ames实验对两者的抗突变特性进行比较得出,水豆豉的抗突变效果略微优于纳豆。     

Evaluation of comparative and combined antimutagenic potential of vitamin C and vitamin E using histidine mutant <Emphasis Type="Italic">Salmonella typhimurium</Emphasis> strains

Chemoprevention represents a new intervention strategy to control some type of carcinogenesis especially in subjects at high risk for cancer development. Experimental and epidemiological data indicate that a variety of nutritional factors including vitamin C and E are effective to lower the risk of some types of cancer. However large prospective studies have failed to find such significant association. A comparative and combined in vitro antimutagenic potential of two antioxidant vitamins ascorbic acid (vitamin C) and α-tocopherol (vitamin E) were evaluated using Ame’s Salmonella typhimurium test assay. Directly acting mutagens such as sodium azide (NaN₃) and 4-Nitro-o-phenylenediamine (NPDA), and N-methyl-N′-nitro-N-nitrosoguanidine (MNNG) were used to induce mutation in salmonella strains TA 98 and TA 100. Vitamin C significantly (P < 0.01) and dose dependently inhibited the mutagenicity induced by all the three mutagens. The percent inhibitions of vitamin C at 15 mg/plate were 33.8% (NaN₃), 52.5 % (MNNG) and 55.4 % (NPDA). Vitamin E (15 mg/plate) was effective to inhibit mutagenicity induced by NaN3 and MNNG but did not inhibit mutation induced by NPDA. Combination of vitamins (vitamin C plus vitamin E) produced only an additive antimutagenic activity when compared to their activity at 5 mg/plate. The results of the study concluded that vitamin C is a better antimutagenic agent than vitamin E and combination of vitamins did not produce any synergistic activity.