Jobling Stephen A, Westcott Roger J, Tayal Akash, Jeffcoat Roger, Schwall Gerhard P
Unilever Research, Colworth House, Sharnbrook, Bedford MK44 1LQ, UK.
Nat Biotechnol. 2002 Mar;20(3):295-9. doi: 10.1038/nbt0302-295.
The use of unmodified starches in frozen foods is severely limited by the undesirable textural changes that occur after freezing and thawing. Retrogradation of glucan chains leads to syneresis, a separation of the starch gel and water phases. Stabilization of the starch structure is normally achieved by chemical modification to prevent these changes from occurring. We have now created a freeze-thaw-stable potato starch by alteration of starch composition and structure by genetic modification. An amylose-free starch with short-chain amylopectin was produced by simultaneous antisense downregulation of three starch synthase genes. This starch is extremely freeze-thaw-stable and shows no syneresis even after five freeze-thaw cycles. The use of this starch has potential for environmental and consumer benefits because its production requires no chemical modification.
未改性淀粉在冷冻食品中的应用受到冷冻和解冻后出现的不良质地变化的严重限制。葡聚糖链的回生会导致脱水收缩，即淀粉凝胶和水相分离。通常通过化学改性来实现淀粉结构的稳定，以防止这些变化发生。我们现在通过基因改造改变淀粉组成和结构，创造出了一种冻融稳定的马铃薯淀粉。通过同时反义下调三个淀粉合酶基因，产生了一种不含直链淀粉且具有短链支链淀粉的淀粉。这种淀粉具有极高的冻融稳定性，即使经过五次冻融循环也不会出现脱水收缩现象。这种淀粉的应用在环境和消费者方面具有潜在益处，因为其生产无需化学改性。
