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Due to the nutritional value of rice cakes, there is renewed interest in this traditional Korean food, and thus various efforts have been made to improve its storage stability. In this study, lactic acid bacteria that produce exopolysaccharides (EPS) were isolated and their physiochemical properties were analyzed. The bacteria were used to produce ‘Sulgidduk’ (a Korean rice cake) with improved storage stability. Among the 107 strains isolated from traditional fermented foods, only five strains were confirmed to produce EPS in MRS media with 10% sucrose. Two of these strains were identified as members of the genus Weissella and three were identified as the Bacillus genus via sequence analysis of 16S rDNA. Among the five strains, the strain Weissella cibaria JNU29 was selected for application to ‘Sulgidduk’, since it is food applicable, viable in artificial gastric and bile juices, and produces the highest content of EPS (16.72 g/L). TLC and HPLC analysis showed that the EPS produced by W. cibaria JNU29 strain was a homopolysaccharide composed of only glucose. A culture solution of the W. cibaria JNU29 strain was mixed with milled rice flour to prepare ‘Sulgidduk’. After incubation for 48 h, the ‘Sulgidduk’ showed lower hardness values than that of the control without the culture solution, and the lactic acid bacteria survived to a level of 7 log CFU/g. Thus, the W. cibaria JNU29 strain, which produces EPS, can be applied for the production of ‘Sulgidduk’, as it delays retrogradation and prevents mold-induced decay to improve shelf life.

Kiwifruit (Actinidia chinensis, Hayward) was stored at 25℃ for 0~30 days and investigated to find out the optimum storage time to obtain the best physical and functional properties for consumers’ preference. Kiwifruits was stored at different time period (0, 5, 10, 15, 20, and 30 days) for investigating their physiochemical quality, nutritional components, and functional characteristics. Kiwifruits stored for 20~30 days showed the best physiochemical quality such as higher total acidity and proper firmness. They were also more enriched with dietary fibers, free sugar, and organic acid, although no significant changes were observed in crude protein, crude fat, and moisture content. For functional properties, kiwifruits stored for 20 days showed significantly higher contents of total phenolics, flavonoids, and actinidin. In addition, it showed stronger antioxidant activity, whitening effect, and proteolytic activity when compared with other samples. SDS-PAGE analysis showed the presence of actinidin enzyme in kiwifruits. These results indicated that the kiwifruits stored for 15~20 days possessed excellent quality and high concentrations of nutritional and functional compounds, which could be best for both fresh consumption and product processing

전남농업기술원 식품연구소This study was carried out to optimize the filtration, clarification, anti-browning processing conditions of clear pear juice and to investigate changes in antioxidant activity of pear juice produced through different heating treatment. For the filtration with cheese cloth, filter paper, or centrifugation (10 min at 3,000 rpm), the pear juice was most efficiently filtered with centrifugation because it showed the highest lightness (L value) and lowest yellowness (a value). Among various clarifying agents, 1% of gelatin or bentonite clarified effectively pear juice but tannin or egg albumin did not. Among anti-browning agents (0.1%) like L-ascorbic acid, NaCl or citric acid, L-ascorbic acid prevented the browning of pear juice with the lowest browning index value (2.62), compared to that of NaCl (2.74), or citric acid (2.87). Fructose, sucrose, glucose and sorbitol were present in the pear juice, the fructose and glucose contents increased but that of sucrose decreased in the heated pear juice. The total polyphenol content of the heated pear juice significantly increase, and did the total flavonoid contents in the clear and heated pear juice. The DPPH radical scavenging activity and nitrate scavenging activity were higher in the clear and heated pear juice than in the fruit crush. Key words antioxidant activity, clarification, Chuhwangbae, pear juice

This study was performed to confirm physiological activities according to parts of new pear cultivars (Gamcheonbae, Manpungbae, Chuwhangbae, Hanareum) and Niitaka pear. The total polyphenol compound contents of pear peel, flesh and core were 178~235, 95~113, 177~229 mg/100 g as tannic acid equivalent, respectively. There were differences in the contents by cultivars, Chuwhangbae and Hanareum cultivars showed high contents. The total flavonoid contents of the pear peel, flesh and core were 29.2~40.2, 24.3~34.3, 26.9~38.8 mg/100 g, respectively and those of Chuwhangbae and Gamcheonbae cultivars showed comparatively high values. The electron-donating ability was high in Chuwhangbae, Gamcheonbae and in the pear peel (29.7~57.7%), core (29.1~38.2%), flesh (7.6~17.7%), in that order. The nitrate scavenging activity was highest in that pear peel (21.0~49.8%), followed by the core (11.8~16.2%) and flesh (7.8~9.7%), but there was little difference by cultivar.