农业工程学报2017，Vol.33Issue(8)：278-285,8.DOI:10.11975/j.issn.1002-6819.2017.08.037
低压静电场下不同隔距冻结-解冻对牛肉品质的影响
Effects of different gauges under low voltage electrostatic field assisting thawing-freezing on beef quality
摘要
Abstract
To research the effect of low voltage electrostatic field (LVEF) assisted freezing-thawing on beef quality, using bovine longissimus dorsias experimental materials, the beef quality of samples at the distance of 15, 30, 45 and 60 cm away from the electrostatic field generating plate (test group) and without LVEF treatment (control group) was studied during freezing-thawing process. The test group and the control group had the same freezing temperature of-18℃ and thawing temperature of 4℃. The indices including freezing-thawing temperature curve, color, thawing loss, protein content of thawing drip, cooking loss, texture profiles were compared and analyzed. Scanning electron micrograph (SEM) and transmission electron microscope (TEM) were used to observe the microstructure of muscle, and the ice crystal morphology in muscle fiber tissue was observed under light microscope. During the process of freezing, the temperature curve showed that LVEF had accelerated the freezing process of beef samples, and the time used in the zone of the maximum ice crystal formation was shorter compared to the control group. Accordingly, the ice crystals in muscle fiber tissue were smaller and uniformly distributed under LVEF. From the thawing temperature curve, it was found that the thawing speed of treatment group was faster. After the process of thawing, several indices were determined. The result showed that LVEF could significantly increase lightness (L*) value, redness (a*) value, chroma (C) value, tenderness and chewiness (P<0.05). In addition, cooking loss, thawing loss and protein content of thawing drip were significantly decreased by LVEF (P<0.05). SEM and TEM showed that the muscle microstructures of control group and treatment group were both damaged after freezing-thawing process. The microstructure of muscle fiber bundles of control group was damaged more seriously, and more muscle fiber bundles were torn and a visibly larger gap was exhibited between muscle fibers, while the muscle microstructure of treatment sample was less damaged and the fiber bundles were relatively tight. Particularly, the samples at the distance of 30 cm away from the electrostatic field generating plate (LVEF30) required the shortest time to finish the process of freezing and thawing, and the time used in the zone of the maximum ice crystal formation was only 290 min, which was shortened by 66% compared with the control group. LVEF30 formed the smallest and most uniform ice crystals, and the muscle fiber tissue was less damaged by ice crystals. SEM showed that LVEF30 maintained the structure of muscle fibers and perimysium effectively, and the gap between muscle fibers had no obvious expansion. TEM showed that Z-disc and M-disc remained relatively intact and A-band and I-band were still clear and legible, which indicated that LVEF30 maintained the integrity of the myofibrillar structure effectively. TheL* value,a* value andC value of LVEF30 were 39.47, 21.77 and 23.71 respectively, which were significantly higher than 31.74, 17.76 and 20.73 of the control group (P<0.05), and had no significant differences with the fresh meat (P>0.05). Thawing loss, protein content of thawing drip and cooking loss of LVEF30 were reduced 4.18, 8.28 and 0.7 percent points, respectively, compared to the control group, and the difference was also significant (P<0.05). The experimental results show that LVEF is able to alleviate the deterioration of beef quality during the freezing-thawing process and improve the quality of the thawed beef significantly, and the most suitable gauge for treatment group is 30 cm.关键词
电场/农产品/品质控制/低压静电场/隔距/冻结解冻/牛肉Key words
electric field/agricultural products/quality control/low voltage electrostatic field/gauge/freezing-thawing/beef分类
轻工纺织引用本文复制引用
李侠,钱书意,杨方威,孙圳,尚柯,张春晖..低压静电场下不同隔距冻结-解冻对牛肉品质的影响[J].农业工程学报,2017,33(8):278-285,8.基金项目
国家自然科学基金项目(31371797) （31371797）
新疆民族特色食品产业升级技术研究与示范项目(2016A01001) （2016A01001）
