Evaluation of the quality and germicidal action of fresh pork chop treated by spraying coated with Chinese mahogany (Toona sinensis) extracts during storage at 10±2℃

• Main Authors: Zih-Huan Lin, 林子桓
• Other Authors: 劉登城
• Format: Others
• Language: zh-TW
• Published: 2014
• Online Access: http://ndltd.ncl.edu.tw/handle/r6r3mz

碩士 === 國立中興大學 === 動物科學系所 === 102 === The microorganisms can lead the decay of the foods and also can cause food poisoning. Since the microbial growth is undesirable, the food industry usually utilize chemical additives in the processing to slow or inhibit their growth. However it has been shown that use of chemical additives can increase the risk of carcinogenesis. According of many reports, the phenolic compounds have excellent antimicrobial activity and can retard the microbial proliferation in food. Therefore, the purpose of the first part in this research was to detect the minimum inhibitory concentration (MIC) of Toona sinensis extract against Staphylococcus aureus, E. coli, Salmonella typhimurium, Pseudomonas aeroginosa, Clostridium perfringens, Candida albicans, Aspergillus flacvu and Cladosporium herbarum. The secondary part, the antimicrobial activity of different concentrations of T. sinensis solutions (0, 125, 250 and 500 μg/ml), positive control (70% alcohol) will be evaluated with the microbial and the quality profiles of pork loin chops which treated by spray coated with T. sinensis solutions during storage at 10℃ for 14 days. The results of the first part in this study, the minimum inhibition concentration (MIC) of T. sinensis extract only for E. coli, P. aeroginosa, S. typhimurium, S. aureus, C. perfringens and C. albicans were 15.625, 15.625, 7.8125, 7.8125, 15.625 and 7.8125 μg/mL, individually. The mixture of T. sinensis and H. cordata or only T. sinensis shown no microbial inhibitory effect against A. niger and C. herbarum. The results of the secondary part in this study, the pH value of all lots increased with storage time; control and positive control were significantly higher than all T. sinensis solution treatments after 10 days of storage. The VBN value of control and positive control increased rapidly with storage time and the value were 27.04and 25.90 mg% at the 10th day during storage. However, the VBN of fresh pork chop spray coated with 250 and 500 μg/mL T. sinensis solution were kept stable and lower value during storage time. The results of TBA value were showed as the same as VBN in this study but that of the control was increased rapidly to 6.36 mg MDA/kg before 5days during storage then decreased down. The profiles of microbial, the total plate count of control and positive control increased siginficantly during storage time, and reached 107 CFU/g at the 7th days of storage. The same number of plate count of fresh pork chop spray coated with different T. sinensis solutions were prolonged to the end of storage (14 days). The results of anerobic count shown as the same as total plate count in this study but all treatments with T. sinensis solution kept lower count (106 CFU/g) until the end of storage. The L* value of all lots significantly increased with storage time but had no significant difference among treatments. The a* value of fresh pork chop spray coated with different T. sinensis solutions maintained stable during storage but control and positive control were significantly decreased with storage time. Moreover, the b* value of all lots were stable during storage. The profiles of sensory panel in all lots of fresh pork chops were decreased significantly with storage time but no significant differences were found at day 0. Based on color score, the fresh pork chops in control and positive control were unacceptable at the 7th day but pork chops treated by 250 and 500 μg/mL T. sinensis solution were still acceptable by people. Furthermore, based on odor and overall acceptance, fresh pork chops of control and positive control can not be acceptable after 3 days of storage and the acceptable time of fresh pork chops treated by 250 and 500 μg/mL T. sinensis solution were prolonged to 7 days of storage. The profiles of sensory panel in all lots of pork chops after cooking were as the same as that in fresh pork chops, based on flavor and overall acceptance. However, the juiciness and texture of all lots of pork chops after cooking were kept acceptance by the sensory panelists until at the 7th day of storage. Altogether, according to analyses of the above microbiological data, the shelf life of fresh pork chops treated by 125, 250 and 500 μg/mL T. sinensis solution can be prolonged to 10 days when compared to 5 days of storage for control or positive control at 10℃. On the other hand, based on the profiles of sensory panel in cooked pork chops, the shelf life of fresh pork chops treated by 125, 250 and 500 μg/mL T. sinensis solution should be shorted to 7days of storage at 10℃.