Biotechnology Division, CSIR-Institute of Himalayan Bioresource Technology, Palampur, Himachal Pradesh 176 061, India.
Biotechnology Division, CSIR-Institute of Himalayan Bioresource Technology, Palampur, Himachal Pradesh 176 061, India.
Food Chem. 2020 Aug 1;320:126599. doi: 10.1016/j.foodchem.2020.126599. Epub 2020 Mar 11.
Antifreeze proteins restrict the growth of ice crystals during recrystallization and therefore find application in the protection of food products from damage upon freezing. Hippophae rhamnoides (seabuckthorn) is a freeze tolerant Himalayan shrub exhibiting antifreeze properties. Here, ~39 kDa class IV chitinase (HrCHI4) was purified from seabuckthorn seeds using chitin-affinity chromatography that showed antifreeze property by ice recrystallization inhibition. The application of HrCHI4 in cryopreservation of green beans was analyzed to verify its antifreeze potential. HrCHI4 pretreatment reduced the drip loss and electrolytic leakage in frozen beans, revealing that it preserved the membrane integrity upon cryopreservation. The texture analysis and SEM further validated structural maintenance. The volatile component analysis using GC-MS was performed to evaluate the quality of frozen beans. HrCHI4 contributed positively towards the retention of volatile components after freeze-thaw. In conclusion, a class IV chitinase HrCHI4 was purified from seabuckthorn seeds and its cryoprotective function was reported.
抗冻蛋白在重结晶过程中限制冰晶的生长，因此在保护冷冻食品免受损害方面有应用。沙棘（海红果）是一种耐冻的喜马拉雅灌木，具有抗冻特性。本研究中，通过几丁质亲和层析从沙棘种子中纯化了~39 kDa 的 IV 类几丁质酶（HrCHI4），该酶通过抑制冰晶重结晶表现出抗冻特性。分析了 HrCHI4 在绿豆冷冻保存中的应用，以验证其抗冻潜力。HrCHI4 预处理可降低冷冻绿豆的滴水损失和电解质渗出，表明其在冷冻保存过程中保持了膜的完整性。质构分析和 SEM 进一步验证了结构的维持。采用 GC-MS 进行挥发性成分分析，以评估冷冻绿豆的品质。HrCHI4 有助于在冻融后保留挥发性成分。总之，从沙棘种子中纯化了一种 IV 类几丁质酶 HrCHI4，并报道了其冷冻保护功能。
