The Quality Control Technology In Drying Process Of Pumpkin Powder

Pumpkin is medicine and food homologous,with the unique nutrition,and has good health and medicinal value.The pumpkin is processed into pumpkin powder,which can be used as a base material for a variety of foods and health foods to extend the shelf life of pumpkin,reduce the cost of storage and transportation,and increase the added value of products.Pumpkin contains low molecular sugars,which are prone to glass transition during drying,leading to sticky walls and collapse,resulting in unstable product quality.In-depth research the effect of pumpkin powder drying process on glass transition and related quality,which is the basis of improving the quality of pumpkin powder and production technology level.Fresh ripe pumpkin as the raw material,this paper studied the effects of drying method on the quality of pumpkin powder,spray drying conditions and physicochemical composition in pumpkin pulp on the glass transition and quality of pumpkin powder,and optimized the condition of spray drying pumpkin powder.The main results and conclusions were as follows:1.Effect of drying method on quality of pumpkin powderThe pumpkin was used as the raw material,and the pumpkin powder was prepared by hot air drying,vacuum microwave-hot air combined drying,spray drying and vacuum freeze drying.The four kinds of drying methods were compared to the color,physicochemical properties,polyphenols,and antioxidant of the pumpkin powder.The impact of sex and other indicators.The results showed that: Spray drying(SD)pumpkin powder has the largest L*value,the highest brightness,the smallest a* value,the lightest color,the better oil holding power,and the largest WSI.After the ultra-fine wet method,the soluble substances are more easily eluted and the particle size span is the smallest.The granules are relatively uniform and have better retention of pumpkin polysaccharides,and have better economic applicability.Hot air drying(HAD)squash powder has better fluidity,better expansibility and water holding capacity,and has the highest DPPH free radical scavenging rate.The Microwave vacuumdrying(MV-HAD)has a higher bulk density and the color is similar to that of the HAD pumpkin powder.The Vacuum freeze drying(VFD)maintained the best color of the pumpkin pink,the closest to the pumpkin primary color,the smallest particle size,the highest total polyphenol content,and the strongest reducing power.2.Effect of inlet air temperature and feed flow rate on glass transition and quality of Spray-dried pumpkin powderThe pumpkin powder was used as the raw material and the pumpkin powder was spray dried.The effects of inlet air temperature and feed flow rate on the glass transition and quality of pumpkin powder were studied.The results showed that the glass transition temperature increased first and then decreased with the increase of inlet air temperature.The moisture content first decreased and then rose.The polysaccharide content of pumpkins first increased and then decreased.With the increase of feed flow,the glass transition occurred.The temperature is on the rise,the water content drops first and then rises,and the pumpkin polysaccharide content shows an upward trend.3.Effect of physical and chemical components of pumpkin pulp on glass transition and quality of spray-dried pumpkin powderThe pumpkin powder was used as the raw material to spray dry the pumpkin powder.The effects of malt dextrin addition and solid content on the glass transition and quality of pumpkin powder were studied.The results showed that with the increase of maltodextrin content,the glass transition temperature showed an upward trend,and the water content decreased first and then increased.The content of pumpkin polysaccharide increased first and then decreased.With the increase of the solid content,the glass transition temperature increased.The transition temperature showed an upward trend,the moisture content decreased,and the pumpkin polysaccharide content first decreased and then rose.4.Spray drying process for the production of pumpkin powderThe four-factor and three-level orthogonal experiment were used to optimize the technological conditions for the preparation of pumpkin powder by spray drying.The results showed that the inlet air temperature was 170℃,the feed flow rate was 70 mL/min,the malt dextrin content was 35%,and the solids content was 8%.Pumpkin powder has a moderate degree of glass transition and pumpkin polysaccharide has the highest content.