• Journal of Food Hygiene and Safety
• /
• v.13 no.2
• /
• pp.99-105
• /
• 1998

Pectin hydrolysate prepared from citrus pectin by enzymatic hydrolysis has antimicrobial activity. The antimicrobial activity was increased by its hydrolyzing rate and it was rapidly increased after 70% hydrolysis of the pectin. The antibacterial activity of pectin hydrolysate against Escherichia coli ATCC 11229 was the strongest at pH 4.9~5.5, but it diminished slightly at neutral pH values. The antibacterial activity of pectin hydrolysate was stronger than those of against molds and yeasts. The growth of bacteria submitted to this test except lactics was completely inhibited for 48 hrs at $35^{\circ}C$ by adding 2.0~3.0% pectin hydrolysate. While the growth of Lactococcus lactis ATCC 19435 and Lactobacillus bulgaricus and Penicillium funiculosum ATCC 11797 were reached about 60~70% compared with those of the controls in the same condition. But there was no significant effect on the growth of the yeasts. The antibacterial effect of pectin hydrolysate was significantly stimulated by addition of glycine, ethanol, sodium ascorbate, sodium chloride and sodium acetate. The shelf life of Kimchi containing 1.0% pectin hydrolysate was prolonged above 15 days at $4^{\circ}C$ than that of its control. In case of whitish bean jam viable cell counts were inhibited about 2 log cycles by 10 days at $25^{\circ}C$. According to these results, author can sincerely suggest that pectin hydrolysate will be used as a natural food preservative for inhibition of common bacterial growth without inhibition of lactics and yeasts.

• Korean Journal of Food Science and Technology
• /
• v.33 no.6
• /
• pp.693-699
• /
• 2001

ChlorophyII destruction by irradiation in linoleic acid in methanol system was studied. ChlorophyII b standard (3 ppm) was added into methanol solution containing 1% of linoleic acid, and the sample was irradiated up to 20 kGy with or without nitrogen gas-bubbling. The content of chlorophyII b was analyzed by HPLC, and Hunter color value and UV-visible spectra were analyzed during 6 hr of photooxidation. The content of chlorophyll was reduced by irradiation and completely destroyed at 2.517 kGy. The model system with nitrogen gas-bubbling did not develop the lipid oxidation after irradiation or photooxidation at 20 kGy UV-visible spectra showed decreasing values of optical density by increase of irradiation doses, supporting the destruction of chlorophyII b. The results indicate that irradiation technology can be applied to reduce or eliminate the residual chlorophyII and to prolong the shelf-life of oil products.

• Food Science of Animal Resources
• /
• v.26 no.3
• /
• pp.322-330
• /
• 2006

Sixteen semimembranous muscles were removed from sixteen left pig carcasses. They were cut into $7{\times}10{\times}2cm$ pieces and mixed randomly. Samples were assigned to four treatments: (T1) soy-based sauce; (T2) Kimchi-based sauce; (T3) pickled shrimp-based sauce; and (T4) onion-based sauce. Each sample was aged in a plastic box at $1^{\circ}C$ for 10 days, then vacuum packed and held at $1^{\circ}C$ for 28 days. The lightness and redness values of the aged pork were, in most cases, significantly increased on the surface and in the interior (p<0.05) by day 28 for all treatments, relative to day 1. The thiobarbituric acid reactive substances (TBARS) value significantly (p<0.05) increased for T1 and T4 from day 1 until day 14, but decreased after 14 days of storage (p<0.05). The TBARS value for T3 decreased with storage time (p<0.05), although there was no difference between 14 and 28 days. The total volatile basic nitrogen (VBN) content increased significantly with storage time (p<0.05) for all treatments, with the exception of T2. Total plate counts (TPC) increased significantly (p<0.05) with increasing storage time for all treatments. On day 1, T2 had the highest TPC value (p<0.05), while T4 was lowest (p<0.05). On 28 day, T2 had the lowest TPC value (p<0.05), while T3 was highest (p<0.05). E. coli levels showed a significant (p<0.05) decrease with increased storage for T1, T2 and T4. These results indicate that T2 was move effective at inhibiting the growth of E. coli than the other pork samples. The levels of Lactobacillus spp. increased with storage time for all samples. These results suggest that traditional Korean ingredients could be utilized to extend the shelf-life of aged pork during storage.