Evaluation of processing conditions on the characteristics and storage qualities of dripping chicken essences extracted from different chicken breeds

• Main Authors: Yi-Chen Lin, 林乙晨
• Other Authors: 譚發瑞
• Format: Others
• Language: zh-TW
• Published: 2016
• Online Access: http://ndltd.ncl.edu.tw/handle/92764689425430503018

碩士 === 國立中興大學 === 動物科學系所 === 104 === The objective of this study was to compare the difference of processing conditions on the characteristics of dripping chicken essences extracted from different chicken breeds. At the first stage, the commercial red-feather native chickens were used to extract dripping chicken essence. The different processing treatment conditions including high temperature for long time (115˚C, 6h, HL), high temperature for short time (115˚C, 4h, HS), low temperature for long time ( 105˚C, 6h, LL) and low temperature for short time ( 105˚C, 4h, LL). At the second stage, the best condition observed in the first stage was applied to compare the nutrients and sensory characteristics of the dripping chicken essence made with five chicken breeds, including native red-feather chicken (NR), native black-feather chicken (NB), broiler (BR), native red-feather hen (RH) and three-way hybrids (TW). In the first stage, the HL treatment had higher yield, crude protein and ash contents; however, HL treatment had the lowest aroma, flavor and overall acceptability for the descriptive sensory and consumer hedonic sensory evaluation. The HS treatment had higher descriptive sensory and consumer hedonic sensory results than the other treatments. Therefore, the HS treatment was selected for preparing the dripping chicken essence at the stage 2. In the second stage, the TW sample had the lowest yield, whereas the NR and NB samples had the highest crude protein and ash contents, as well as the lower water contents. RH and TW had the lowest crude protein and ash contents and the highest water content. This results might be because of most of the fat were removed after extraction, leading to the crude fat content in the chicken extract was less than 1% in all samples. The BR and NR samples had the highest lightness, while the NR sample had the highest redness and yellowness values. The BR sample had the highest pH value, while the NR and RH samples had the lowest pH values. The native samples had higher total collagen content than broilers and hens, which the NB sample had the highest content. In this study, it was observed that the NR sample had the highest salt content, and the lowest salt content was observed in the RH sample. For the hydrolyzed amino acid content of dripping chicken essence, the native chickens had higher total amino acid and essential amino acid contents than broilers and hens, whereas the NB sample had the highest content and the RH sample had the lowest content of the hydrolyzed amino acid. For the free amino acid content, the BR sample had the highest total free amino acid, whereas the NR sample had the highest contents of taurine, carnosine and anserine. For the descriptive sensory evaluation, the NR and NB samples had darker color, stronger meat flavor and umami flavor than others; however the NB had stronger off-odor than the NR sample. There were no significant difference in rancid flavor, saltiness and bitterness between treatments. Finally, no significant difference was observed on the hedonic sensory results between the treatments. At the third stage, the dripping chicken essence made from NR and BR had significantly lower L* value and significantly higher b* value during the storage at -20˚C for 12 weeks. The pH values of NR and BR dripping chicken essences slightly decreased during storage. The TBARS value in both NR and BR dripping chicken essences showed no significant difference until week 3 of storage and gradually increased after week 4 of storage and noticeable increased at week 12 of storage. NR dripping chicken essence showed higher TBARS value than BR one. No significant difference in the sensory evaluation in both of samples during storage; however, consumers preferred NR sample than BR one. In conclusion, although the dripping chicken essence produced with high temperature and short time (115 ˚C / 4 H, HS) had the secondary of physicochemical performance such as yield, crude protein and ash contents; however, the HS treatment had the highest sensory acceptability results. The physicochemical and characteristics of the dripping chicken essence might be affected by the chickens that applied in the process. Such differences might be due to the influences of breed, age, feed and others. No significant difference was observed on the sensory characteristic between the dripping dripping chicken essence made with different chickens. The dripping chicken essence could be stored at -20˚C at least for 12 weeks with acceptable qualities.