Larder Christina E, Baeghbali Vahid, Pilon Celeste, Iskandar Michèle M, Donnelly Danielle J, Pacheco Sebastian, Godbout Stephane, Ngadi Michael O, Kubow Stan
School of Human Nutrition, McGill University, 21,111 Lakeshore, Ste. Anne de Bellevue, QC H9X 3V9, Canada.
Bioresource Engineering, McGill University, 21,111 Lakeshore, Ste. Anne de Bellevue, QC H9X 3V9, Canada.
Foods. 2019 Sep 2;8(9):382. doi: 10.3390/foods8090382.
Potatoes ( L.) are a good dietary source of carbohydrates in the form of digestible starch (DS) and resistant starch (RS). As increased RS content consumption can be associated with decreased chronic disease risk, breeding efforts have focused on identifying potato varieties with higher RS content, which requires high-throughput analysis of starch profiles. For this purpose, freeze drying of potatoes has been used but this approach leads to inaccurate RS values. The present study objective was to assess the starch content (RS, DS and total starch (TS)) of three cooked potato genotypes that were dried using freeze drying and innovative drying techniques (microwave vacuum drying, instant controlled pressure drop drying and conductive hydro-drying) relative to freshly cooked potato samples. Depending on the genotype, all drying methods showed one or more starch measures that were significantly different from freshly cooked values. The combination of ultrasound and infrared assisted conductive hydro-drying was the only method identified to be associated with accurate assessment of DS and TS content relative to fresh samples. The drying treatments were all generally associated with highly variable RS content relative to fresh controls. We conclude that freshly cooked samples must be used for selecting varieties with a high proportion of RS starch as drying of cooked potatoes leads to unreliable RS measurements.
马铃薯（L.）是易消化淀粉（DS）和抗性淀粉（RS）形式的碳水化合物的良好膳食来源。由于增加RS含量的摄入可能与降低慢性病风险相关，育种工作集中在鉴定具有较高RS含量的马铃薯品种，这需要对淀粉谱进行高通量分析。为此，已采用马铃薯冷冻干燥法，但这种方法会导致RS值不准确。本研究的目的是评估三种煮熟的马铃薯基因型的淀粉含量（RS、DS和总淀粉（TS）），这些基因型分别采用冷冻干燥和创新干燥技术（微波真空干燥、瞬间控制压力降干燥和传导液力干燥）进行干燥，并与新鲜煮熟的马铃薯样品进行比较。根据基因型的不同，所有干燥方法均显示出一种或多种淀粉测量值与新鲜煮熟的值存在显著差异。超声和红外辅助传导液力干燥相结合是唯一一种被确定与相对于新鲜样品准确评估DS和TS含量相关的方法。相对于新鲜对照，干燥处理通常都与高度可变的RS含量相关。我们得出结论，由于煮熟马铃薯的干燥会导致RS测量值不可靠，因此必须使用新鲜煮熟的样品来选择具有高比例RS淀粉的品种。
