E. coli mutant has been used as an assay organism for vitamin B12activity by many workers. The difficulty encountered in this method is theinterfering-action of metmonine. Fermented soybean products contain large.amount of this amino acid, thus the usual alkaline treatment method could not be used for the determination of vitamin B12 activity in these.products. A method for the separation of vitamin B12 from methionine has been developed by the authors. The sample extracted is prepared by the usual method and the extract passed through an active carbon absorption column, Then washing the column with pH 4.5 sodium acetate buffer solution removes methionine and finally vitamin B12 is eluted off with hot 65% alcohol Alcohol in the eluate is removed under reduced pressure and the methionine in the residue is in trace amount which can be corrected by the alkaline treatment. The recovery of vitamin B12 from the adsorption treatment ranges,from 95% to 101.3%, with an average of 98.8%.Nine kinds of Chinese -fermented soybean products have been assayed by this method. Fermented soybean curd with strong smell is a good dietary source of vitamin B12 activity, and it contains 1.88-9.80 r per 100 grams.

The change of the ascorbic acid content in several vegetables at the different steps in the cooking process was studied. Special attention was directed to washing before or after cutting the vegetable into pieces of different size.Large-scale and household cooking methods were compared. The effect of storing the cooked vegetable at different temperatures and for different lengths of . time was also investigated.The loss of the total and reduced ascorbic acid in spinach, colza, cabbage and celery cabbage was insignificant after washing either before or after cutting. The loss was also not appreciable when these vegetables were held for 2 and 6 hrs. after cutting into wedges. When potatoes and cabbage were cut into strips, there was no change in the total ascorbic acid but a slight decrease of the reduced form. A marked loss of total ascorbic acid was observed when potatoes strips and slices were soaked in water; the slices lost 11.2% and 12,.8% and the strips lost 22.6,% and 23.9% respectively by the end of 2 and 6 hrs. When potatoes were cut and kept in the air at room temperature for 2 and 6 hrs., there was no change in total ascorbic acid, but an increase of the reduced form was apparent. Such an increase should not be attributed to the so-called "traumatic formation"; some changes in the redox system of ascorbic acid is to be expected.A certain amount of ascorbic acid was lost when'spinach, garlic green, colza and celery cabbage were cooked either in large or in small quantities. The retention of the reduced ascorbic acid in the vegetables cooked in small quantit ies ranged 50.2-64.1.%, and that of the total ranged 72.6-75.7%. In case of the large-scale cooking, the retention of reduced and total ascorbic acid ranged 53.6-70.5% and 73.9 - 85.4% respectively. No loss of ascorbic acid was observed when the potatoes were steamed whole, but a large amount was lost when their strips were scrambled in a Chinese style.Cooked vegetables held at 60℃ for 2 and 4 hrs. lost a part of its ascorbic acid; the percentage of loss in the 2 hr. period was lower than that in the 4 hr.

The change of ascorbic acid and carotene content in spinach, small cabbage, cabbage, tomato and Chinese cabbage during storage had been investigated. When spinach was stored at 11-19℃ for 8 days, 26％ of the reduced and 43％ of the total ascorbic acid were retained. Spinach, stored at 16-26℃ for 8 days, retained 16％ of its reduced and 54％ of its total ascorbic acid content and, at 0-2℃ for 23 days, 40％ of the former and 46％ of the latter. Small cabbage, stored at 18-27℃ for 5 days, retained 65％ of its reduced and 73％ of its total ascorbic acid content, but when it was stored at 0-2℃ for 8 days, 86％ of both was retained.Ascorbic acid was found to be more stable in cabbage and tomato during storage. The retention of the reduced form in these vegetables was over 80％ and that of total ascorbic acid over 90％ after 5 days' storage at 21-27℃, and no significant loss of ascorbic acid was observed after 14 days' storage at 0-2℃.Loss of ascorbic acid content in the Chinese cabbage after 4 months' storage in Chinese cellar during the winter season of 1955-1956 was about 20％.Percentages of retention of the carotene content in spinach during the storage at different temperatures with different lengths of time were as follows: 80％ at 11-19℃ for 8 days, 77％ at 16-26℃ for 3 days, and 93％ at 0-2℃ for 31 days. Small cabbage retained 60％ of its carotene content after 5 days' storage at 18-27℃, and 97％ after 8 days at 0-2℃.

Husked and milled rice samples were prepared with laboratory rice mill from 23 representative varieties of paddy collected from the main rice production areas of China. All the samples were analyzed for the contents of protein, fat, crude fiber, ash, calcium, phosphorous, thiamine, riboflavin and niacin. The nutrient content of husked rice varies with variety and locality of growth. The range of protein content of the husked rice samples ranged from 6.7% to 9.6%.Rice samples had been analyzed at successive stages of milling for studying the effect on the nutrient content of milled rice. Results of this investigation showed that nutrient content declines progressively during the process of milling. While the protein content decreased insignificantly, the other nutrients, especially thiamine, ash, phosphorous, crude fiber and fat, were lost to a greater extent. In order to keep the thiamine content of polished rice not less than 0.15 mg %, the authors advocated that the overall weight removed during milling should not exceed 9-10% of the weight of husked rice.

The contents of reduced and total ascorbic acid, vitamins P, reducing and total sugar, citric acid, ash, calcium, crude fibre and moisture in the edible portions of 23 main varieties of Chinese oranges and tangerines have been determined. The change of ascorbic acid content of the fruits during storage has also been investigated.Ascorbic acid content of orange is higher than that of tangerine. Oranges contain 46.6-62.3mg% of reduced ascorbic acid and 48.8-72.4mg% of total ascorbic acid and tangerines contain 14.3-48.7rng% and 19.5-50.7mg% respectively.Locality affects the composition of fruits: fruits grown in Fukien and Kwangtung provinces generally contain more ascorbic acid and .sugar, and less citric acid and calcium than those grown in Kianghsi and Chekiang.Five strains of fruits have been subjected for storage test. The loss of ascorbic acid in the fruits during 2-3 months storage in the winter season ranged 0-40% of the original content. No loss of ascorbic acid has been observed in Hsuehkan (雪柑), after 3 months storage at -2? to 4℃, but loss of 40% of the reduced and 20% of the total ascorbic acid content occurred in Kwangtung chiaokan (广东蕉柑) after two and half months storage muler -1? to 12℃