Study On Quality Characteristics And Nutritional Processing Of Waxy Millet In Guizhou

Millet?Setaria itatica?is a high-quality grain and can be used both as food and medicine.It is rich in protein,fat,yellow pigment,polyphenols and other components.Known as the"king of grains",millet has various medical functions,including antioxidant activity,nourishing stomach and kidney,circulation blood,improving lactescence,enhancing human immunity and so on.Therefore,it have been favored by consumers.Excavating the nutrition and health function,exploring the product processing,and developing millet food are of great significance to meet the needs of life and health care.Therefore,in this paper,the nutritional and functional components,and physicochemical characteristics of main cultivated glutinous millet in Guizhou were analysed and compared.The changes of nutritional and functional components during the steaming process of millet-zha were evaluated.In addition,the high nutritional glutinous adlay was mixed with millet to develop new compound adlay-millet Mochi,and the anti-aging properties of the additives were analyzed.The results showed that:1.The amylose content of Guizhou millet?3.46%⁴.18%?was lower than that of Shanxi millet?19.07%²3.58%?,indicating that the glutinous property of Guizhou millet was stronger.The average polyphenol content?48.12 mg/100 g?of Guizhou millet was higher than that of Shanxi millet?36.35 mg/100 g?,and the polyphenol content of Shibing millet was the highest?87.09 mg/100 g?.The contents of flavonoids?21.65 mg/g?and yellow pigment?4.94 mg/kg?in Shanxi Jingu 29 were higher than that of other samples.Principal component analysis showed that the water solubility index,flavonoids,amino acids,polyphenols and ash content were the key indicators which influenced the quality of millet,and the corresponding cumulative variance contribution rate was 86.37%.Eight kinds of glutinous millet samples were evaluated,and the best variety was Shibing and Zhenning millet.2.During the steaming processing of millet-zha,the polyphenol contents in atmospheric and high-pressure steaming samples decreased firstly and then increased.However,the flavonoids contents were steadily decreased.Compared with the millet-zha with the minimum steaming time?30 min?,the polyphenol content of millet-zha steamed for 60 min at normal pressure and 40 min at high pressure decreased by 4.78%and 1.40%,respectively.When the steaming time were 150 min?normal pressure?and 70 min?high pressure?,the polyphenol content of millet-zha increased by 26.29%and 19.86%respectively in contrast to 30 min.The flavonoid contents in atmospheric?150 min?and high-pressure steam?70 min?were 7.85%and3.43%lower than that in 30 min.The average flavonoid content in high-pressure was13.55%higher than that in normal pressure treatment.The different types of starch contents of millet-zha were determined,and results showed that the contents of rapidly digestible starch?RSD?and slow digestible starch?SDS?of millet-zha processed by high-pressure steaming?30⁷0 min?increased with the steaming time prolonging,and the contents were 70.08%⁷7.88%and 15.89%²0.72%,respectively.The resistant starch?RS?decreased from 14.03%to 1.39%.The change trends of RSD,SDS and RS contents in atmospheric steam?30-150 min?were similar to that in the high pressure.3.The formula of the compound adlay-millet Mochi was optimized.The optimal combination was determined to be the ratio of millet and adlay of 2:1,with the addition of 80%water,20%xylitol and 10%vegetable oil.Except vitamin B₁,the contents of bound phenol,free phenol,yellow pigment and flavonoids of compound adlay-millet Mochi were significantly increased when compared with that of commercial Mochi.4.The influences of additive on anti-aging properties of compound adlay-millet Mochiwere studied.The results showed that monoglyceride and xanthan gum can inhibite the retrogradation of the Mochi.The results of texture analyzer?TPA?and differential scanning calorimetry?DSC?showed that when the additions of monoglyceride and xanthan were 0.3%and 0.2%,the hardness decreased by 56.82%and 26.58%,and the enthalpy decreased by 23.35%and 35.10%,respectively.When of the monoglyceride?0.3%?compounded with xanthan gum?0.2%?,the hardness value?884.50 g?and thermal enthalpy?4.41 J/g?were the lowest,which was better than that of single additive.Nuclear magnetic resonance?NMR?detection indicated that,the signal amplitude was weakened at relaxation time T₂₃,and the free water was reduced when the additive were added to the compounded Mochi.Furthermore,the signal amplitude of T₂₂ was enhanced,and the irreducible water was increased.The T₂₂ signal amplitude was the strongest when the ratio of compounded additives was0.3%:0.2%,and the water holding capacity was optimal during the storage of compounded Mochi.Additives had no significant effect on the crystal form of samples by X-ray diffraction?XRD?.Single or compound additives reduced the intensity of diffraction peaks,crystallization and aging degree.Therefore,0.3%monoglyceride and 0.2%xanthan gum can be used in the preparation of compound Mochi to achieve a better anti-aging effect and edible quality.