Antimicrobial property of sucrose fatty acid esters (SE), and monoglycerol (MG) and polyglycerol fatty acid esters (PGE) were examined in vitro and in postharvest treatment. The growth of gray mold (Botrysis cinerea PEAS.) was suppressed by all SE at a concentration of 1% in the test medium. Caprylic acid (C8) completely suppressed the growth of mold, but the suppression by other SE decreased as the number of carbon of fatty acid increased, such as caprate (C10), laurate (C12), myristate (C14), palmitate (C16) and stearate (C18). Suppression of growth decreased as the concentration of SE in the medium was decreased. Caprylic acid monoglyceride also inhibited the mold growth in the medium. Lauric acid polyglyceride suppressed the growth by 40%; whereas, stearic acid polyglyceride had no effect. The effect of 1% SE and MG on fungal growth on fruit was evaluated as a postharvest treatment. The antimicrobial effect of SE was found in caprylic acid ester treatment but in caprylic acid monoglyceride treatment, not found as apparent in the above in the medium study.
Involvement of ethylene on changes in gas metabolism and fruit color of pineapple fruit after harvest was studied, using 1-methylcyclopropene (1-MCP), an ethylene action inhibitor. Rates of respiration and ethylene production of fruit harvested at mature green stage continued increasing during storage, showing the pattern increasing towards the end of storage, but the maximum ethylene production rate was less than 1 nl g-1 h-1. 1-MCP decreased respiration and temporarily increased ethylene production from the fruit. Propylene, which transiently increased respiration, did not stimulate ethylene production. When whole fruit was separated into fruit part and crown, the pattern of gas metabolism in whole fruit was completely dependent on fruit part, not on crown. Treatment of immature, mature green and ripe fruits with 1-MCP for several times resulted in temporal stimulation of ethylene production immediately after each treatment, irrespective of harvest maturity. Respiration and ethylene production, which increased on the tree as fruit developed, continued increasing after harvest. Fruit color progressed in all fruits harvested at three different maturity, but was delayed by 1-MCP, in which the younger the fruit, the more prominent was the effect of 1-MCP on inhibition of color change. These results indicated that ethylene production in harvested pineapple fruit is controlled by negative feedback regulation (autoinhibition), and that ethylene is involved in fruit color change. Pineapple fruit at least partially perform postharvest ripening since gas metabolism and fruit color in harvested fruits changed just as on-tree fruit.
The glycosylated lactoferrin (gLf) was prepared by the Maillard reaction of the incubation at 60°C under the relative humidity of 78.9% for two weeks. Lactoferrin was completely glycosylated, and native lactoferrin was not found after the glycosylation. The Fe-binding capacity and the excellent emulsifying properties were observed in gLf. The gLf revealed the potent antimicrobial effects. E. coli could not live in the presence of gLf combined with the incubation at 50°C. The preservative effect of gLf on E. coli in the cottage cheese was observed. These results are going to be contributed the further studies on food preservations.
The objective of this study was to develop low-salt pork sausages using pressure processing. Quality of pork sausages manufactured at different salt concentrations (0 %, 1. 0%, 2. 5%), pH (5. 0, 5. 5, 6. 0, 6. 5, 7. 0) and pressure intensities (0, 50, 100, 200, 300, 400 and 500 MPa) was evaluated. Sausages processed at 200 MPa and 1 % NaCl were not significantly different from those produced at the normal NaCl concentration of 2. 5% in terms of water-holding capacity, ratio of restitution, gel strength and work done values. Low-salt sausages processed under the pressure also had high scores for sensory evaluations. At pressures greater than 200 MPa, gels formed after heat treatment were brittle. At pH5. 5 and 6. 0, sausages at 1 % NaC1 had a strong gel when treated at 200 MPa. However, at pH above 6. 5, the gel formation was brittle. From these results, salt concentration of sausage could be reduced by almost 50% compared to the conventional processing methods by using pressure processing. Processing at 200 MPa produced good quality sausages without the use of excessive salt, as well as food additives such as phosphates.