ผลของการลดอุณหภูมิแบบสุญญากาศและบรรจุภัณฑ์แอกทีฟที่แตกต่างกัน ต่อคุณภาพหลังการเก็บเกี่ยวของข้าวโพดหวาน

Abstract

This research was aimed at studying the effect of vacuum cooling, active packaging and vacuum cooling combined with active packaging on the quality of sweet corn. Studying an optimum parameters of the vacuum cooling process for bi-color sweet corn with initial temperature of 20-23°C in order to obtain the final temperature of 4±1°C. Study on quality of precooled bi-color sweet corn during storage was also conducted. Bi-color sweet corn was cooled by vacuum cooling using final pressure of 6.0 millibar with 3 durations of holding time: 15, 20 and 25 minutes. The results showed that the optimum parameter of the vacuum cooling process for bi-color sweet corn was set by the final pressure of 6.0 millibar with the holding time of 20 minutes. During the vacuum cooling process with this optimum parameter, the bi-color sweet corn had weight loss of 2.59 %. Bi-color sweet corn was packed in perforated polyethylene bag prior to storage at 4°C with 80-85% relative humidity. The results showed that the vacuum cooling process had no effect on the changes of kernels color, percentage of weight loss, total soluble solids, vitamin C content, total sugar content, reducing sugar content and starch content. However, bi-color sweet corn cooled by vacuum cooling process had storage life of 11 days, which was shorter than sweet corn in control treatment that was stored for 13 days, in which, at the last day of storage, kernels of bi-color sweet corn in all treatments showed shrinking symptom. Bi-color sweet corn was packed in perforated polyethylene bag, polypropylene bag, active package M1 (OTR of 10,000-12,000 ml/m2-day), active package M2 (OTR of 12,000-14,000 ml/m2-day) and active package M4 (OTR of 14,000-16,000 ml/m2-day) prior to store at 4 °C. The results showed that active package type 1 could extend the loss of fresh weight, delayed vitamin C and total soluble solids degradation, and extended maximum shelf life for up to 19 days, while bi-color sweet corn packed in perforated polyethylene bag had only 13 days shelf life. In addition, the effect of vacuum cooling combined with active packaging (M1) on the physical and chemical quality of bi-color sweet corn was also studied. The results showed that the combined of vacuum cooling with active packaging had not an effect on the physical and chemical quality of bi-color sweet corn.