• Korean Journal of Food Science and Technology
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• v.2 no.2
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• pp.17-25
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• 1970

Juice were extracted from fresh leaves of 70 species of plants growing in Korea by mincing and pressing the resulting pulp through a cotton cloth. Leaf protein concentrates could be prepared from many species of land and water plants that are at present economically unimportant. The choice of plants is of considerable important. Total-N, protein-N and pH determinations were made on the extracts, and total-N remaining in the fibre were calculated. Leaf protein concentrates were precipitated from the extracts at $75{\sim}80^{\circ}C$, and analysed total-N as protein-N of products. The present paper deals with the calculated yields of leaf protein concentrates from various plants, relations between yield of leaf protein concentrates and total-N of leaves, or pH of extracts, and the amino acid compositions of leaf protein concentrates. Results are summarized as follows. 1. Spinach and radish were the best sources of easily extractable, but good results were also obtained with indian mustard, kail, chenopod, red bean, cucumber, squash, houndberry, white flowered gourd, potato, Humulus japonicus, arrowroot and soybean as a good resources for the production of leaf protein concentrates. 2. In general, the greater the protein content of leaves the greater the yield of leaf protein concentrates. However, there are some plants difficult to make a adequate protein extraction by a simple mechanical process. 3. It was to be expected that leaf protein concentrates would be more extractable with the higher pH of extracts. There were a poor yield of the leaf protein concentrate in the pH values lower than 5.50 of the first extracts. 4. Protein content of the leaf protein concentrate shows marked differences, depending on species and season. It ranged between 29 to 80% of protein contents. However, the majority of plants yielded products containing more than 50% of protein. Products containing more than 75% of protein were obtained from two species of radish and indian mustard. Cabbage and Digitaria sanguinalis cilialis (summer) made products containing 29 to 32% of protein. 5. The amino acid composition of leaf protein concentrates was not greatly altered by species of plants. On an amino acid compositional basis, the leaf protein concentrate has a favorable balance of essential and non-essential amino acids, the only exception being methionine, which was usually low in all cases.

• The Korean Journal of Food And Nutrition
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• v.17 no.1
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• pp.25-31
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• 2004

The quality and sensory characteristics of kimchi during fermentation at 15 $^{\circ}C$ were evaluated. Kimchi was prepared with Chineses cabbage which was brined in 10% salt water added dill hot-water extracts(DK) and stevia hot-water extracts(SK) respectively. The pHs and reducing sugar contents of kimchi were decreased with increasing the fermentation time whereas lactic acid(%) was increased. The pH of DK was lower than control, and the lactic acid(%) contents of DK, SK were equal or higher than control in the first stage of fermentation. Also, the reducing sugar contents of DK, SK were lower than control. These results showed that the fermentation of DK and SK were faster than that of control in the first stage of fermentation. But the lactic acid(%) contents of DK, SK were higher than control after the 12th day of fermentation. It showed that it is possible to extend the preservation of kimchi. With increasing fermentation time, the L value of kimchi juice was increased, and the a value was decreased, and the b value was constant. Especially, the a value of DK, SK was higher than control. It meant that DK, SK kept more carotenoids in kimchi than control. On the 6th day of fermentation, the sensory evaluation analyzed by ANOVA followed Duncan's multiple range test showed that the levels of the green smell and the moldy flavor of DK were significantly lower than control(p<0.05) and the levels of the green smell, the green flavor and the moldy smell of SK were significantly lower than control(p<0.05), too. And the level of overall flavor of DK, SK was higher than control. The most preference among experimental groups was SK and then control, DK. The levels of TBARS of DK, SK were generally lower than control, and the level of TBARS of DK was lower than SK.