The Quality Improvement Of Potato Boiling Pretreatment And Its Application Base Study In Low-GI Bread

The purpose of this study was to investigate the effects of boiling treatment on the damage of potato structure.The relationship between potato structure damage and the quality of potato bread,in vitro starch hydrolysis rate was also studied.On the basis of these studies,a potato bread powder with low GI was prepared.Specific research contents are as follows:1.The pretreatment of potato tuber in boiling water at different boiling time and the characterized with fresh potato.The structure of the potato disruption investigated by optical microscopy,conductivity,determinations of malondialdehyde(MDA),iodine-blue measurement,and SEM.The character of the potato disruption investigated by FT-IR spectroscopy,DSC,water binding capacity and oil binding capacity.With the increased of boiling time,potato structure damage was aggravated.2.The cooked potatoes were mixed with wheat flour to make potato bread.The quality and digestive characteristics of potato bread were evaluated.The specific volume,porosity,textural properties,SEM,color and in vitro starch digestibility of potato bread were investigated.The bread sample with 5 min boiled potato content exhibited the best baking properties.Scanning electron microscopy(SEM)revealed that bread samples with mashed potato contents of more than 5min exhibited discontinuous network structures.With the increased of boiling time,the specific volume of potato bread shows a decreasing trend,and the hardness shows an increasing trend.The inside of the bread will show a discontinuous network structure.The rapidly digestible starch contents increased from 24.82% to 45.64% and expected glycemic indices of potato bread increased from 62.50 to 80.89.Thus it can be seen,controlling boiling time is a viable approach to develop potato products with enhanced nutritional functionality.3.Potatoes cooked for 5 min are freeze-dried to make freeze-dried potato powder,which is compounded with wheat flour,vital wheat gluten,TG enzyme,sodium stearoyl lactylate,ascorbic acid,and calcium sulfate four bread improvers.Carry out a four-factor five-level single-factor experiment to optimize the formula of potato bread flour,and the final formula was: 50.00% freeze-dried potato powder,50.00% high gluten powder,with the total amount of freeze-dried potato powder and high gluten powder was 100%,the addition amount of other components is 10% vital wheat gluten,0.05% TG enzyme,1.30% sodium stearoyl lactylate,0.30% ascorbic acid,1.60% calcium sulfate.After the confect is completed,the potato bread flour and the high-gluten flour are compared for nutritional content,flour quality,stretching characteristics,nutritional evaluation and sensory evaluation.It was found that the potato bread flour has a higher content of minerals and crude fiber,and a lower fat content,but it has lower dough processability,fluidity and plasticity than high-gluten wheat flour dough.In terms of digestion characteristics,the digestibility of potato bread is much lower than that wheat flour bread,and it has a higher content of RS and a lower GI value.The sensory evaluation show that the aroma,color and taste of potato bread were recognized by everyone,and it was a low-GI food,which was more in line with the lifestyle of healthy diet of modern people.