真空浸渍技术结合营养强化技术在冻结苹果前处理中的应用

Application of vacuum impregnation and nutritional enrichment in pretreatment of frozen apple(Royal Gala)

真空浸渍技术(VI)可以被用作冻结苹果的前处理。在VI浸渍液中添加营养物质,有助于提高冻结苹果的品质及营养强化。本研究将苹果样品置于6666Pa真空度下,用已添加过葡萄糖酸钙混合物(CG)或乳酸锌(ZL)的20%及50%的高果糖玉米糖浆(HFCS)浸渍15min,并复压30min,同时对样品进行矿物质含量和理化指标的测定。研究得到,经VI后的苹果每200g样品中含钙量可以达到每日参考摄入量(DRI值)的15%～20%,含锌量可以达到40%。各项理化指标表明,浓度为20%的浸渍液对处理后的苹果理化性质的影响较小,但浓度为50%的浸渍液可去除冷冻前苹果中的部分水分,使液汁流失减少57%～60%,还可以增加冻融后苹果柱的抗压能力。此外,添加有机锌的浸渍液有助于增加苹果柱在浸渍和冻融前后的颜色稳定性。

Vacuum impregnation（VI） with nutritive material was used as a pretreatment of freezing apples（ Royal Gala） for improving quality of frozen apple and introducing nutritive material into the fruits, Apple samples were immersed in diluted high fructose corn syrup （HFCS） （20% w/w or 50% w/w） integrated with either calcium gluconate（CG） or zinc lactate （ZL）. Vacuum pressure of 6666Pa was applied for 15min, and then atmospheric pressure was restored for 30min while samples remained in the solution. Mineral content and physicochemical properties of the apples immediately after VI were determined.Results indicated that about 15% to 20% DRI（ Daily Reference Intake） of calcium and above 40% zinc could be obtained in 200g of apples depending on the VI conditions.VI treatments in 20% （w/w） solutions had little effects on the physiochemical properties of Vl apples.But 50%（w/w） solutions could partially remove moisture before freezing and reduce the drip loss 57% to 60% in frozen-thawed apple columns. It could also improve the texture of the apple after frozen and thawed, The VI pretreatment used 50% HFCS solution.Zinc lactate improved color stability of apples during the impregnation and freeze-thawing process.