Study On The Mechanism On Blueing Of Boiled Lotus Rhizome Discs And The Development Of Flavored Lotus Rhizome Discs

Lotus rhizome is rich in nutrients and contains a variety of phenolic substances and minerals,and is widely cultivated in various regions of China.Boiled lotus rhizome discs are one of the main processed products of lotus rhizome,and the lotus rhizome discs without adding color protector will have blueing and subsequent browning during boiling,and the current research on boiled lotus rhizome discs mainly lies in the generation and inhibition of browning,but the formation factors and mechanism of boiling blueing of lotus rhizome discs have not been studied,and the problem of single flavor of boiled lotus rhizome discs has not been solved.In this study,the colour,iron content,total phenolic content and polyphenolic content of lotus rhizome discs were measured before and after cooking in different regions;in vitro experiments were also carried out to investigate the blueing mechanism of boiled lotus rhizome discs and the polyphenols involved in blueing.Secondly,a flavored lotus rhizome discs product consisting of boiled lotus rhizome discs packets and seasoning sauce packets was developed to determine the shelf life of boiled lotus rhizome discs packets while optimizing the production formula of seasoning sauce packets.The results of the study are as follows:1.study on the mechanism of blueing of boiled lotus rhizome discsFresh lotus rhizomes with mud from different months and regions were used as raw materials to analyze the blueing of lotus rhizome discs after boiling in distilled water and the correlation between color,total phenolic content and iron content;the lotus rhizome and polyphenol standards from Wuhan region in November were used as raw materials,and the control group was set as fresh lotus rhizome,and different boiling media were used as experimental groups to determine the color,total phenolic content,iron content,and content of various polyphenols in the polyphenolic extracts of each group.The results showed that after boiling in distilled water,the lotus rhizomes in Suqian area showed serious blueness in March and April;the lotus rhizomes in Cao County area showed serious blueness in March and April in some peripheral areas;the lotus rhizomes in Taizhou area showed almost no blueness in March and slight blueness in April;the lotus rhizomes in Honghu area showed serious blueness in March and almost no blueness in April;the lotus rhizomes in Wuhan area showed serious blueness in March and April,obvious blueness in February,slight blueness in May,and almost no blueness in September and November.The lotus rhizome in Wuhan area has serious blueing in March and April,obvious blueing in February,slight blueing in May,and almost no blueing in September and November.The total phenolic content of different lotus rhizome discs decreased significantly after boiling in distilled water,among which the b*value in the peripheral region after boiling was close to or less than 0 for the lotus rhizome discs with blue discoloration,and the iron content increased significantly.The post-boiling peripheral region b*values were significantly and negatively correlated with the iron content of the fresh root and the iron content of the post-boiling peripheral region.In the peripheral region of the lotus rhizome,the b*values of all treatment groups decreased significantly after boiling in different boiling mediums,but the treatment groups with addition of 0.1%ferrous sulfate solution to the boiling medium showed a more significant decrease in b*values;the total phenolic content in all treatment groups decreased after boiling in different boiling mediums,but the treatment groups with0.1%ferrous sulfate solution added in the boiling medium significantly decreased the total phenolic content The UPLC results showed that the main polyphenols contained in different treatment groups were levodopa,gallocatechin,catechin,p-hydroxybenzoic acid,epigallocatechin,catechol,eugenol,rutin,protocatechuic acid The results of in vitro binding test and Uv-vis showed that the phenolic substances in the boiled root discs complexed with their own iron ions to form blue polyphenol-iron complexes,thus causing the blueing in boiling,in which the main phenolic substances involved were levodopa,gallocatechin and epicatechin.2.Shelf-life prediction of boiled lotus rhizome discsThe shelf life of boiled lotus rhizome packets,one of the two components of the flavored lotus rhizome product,was investigated.The changes in color,hardness,commercial sterility and sensory evaluation of boiled lotus rhizome packets stored at three storage temperatures were examined,and the commercial sterility and sensory scores were selected as characteristic indicators to predict the shelf life using the Q₁₀ model.The results showed that L*,hardness,and sensory score decreased with increasing storage time and the rate of change increased with higher storage temperature when the boiled root packets were stored at 4°C,27°C,and 37°C.The commercial sterility and sensory scores were selected as the characteristic indicators,and the Q₁₀ model was used to predict the shelf life of boiled lotus rhizome packets at 4°C for 601 d and at 25°C for 179 d.3.Process optimization of flavored sauce packetsThe formulation of one of the two components of the flavored lotus rhizome discs package,the seasoning sauce package,was optimized.The results showed that the addition of xanthan gum and guar gum in a ratio of 3:7 to the sauce packets resulted in a better paste rate and sensory score with a reduced amount of thickener compared to a single thickener.In the one-way experiment,the effects of different additions of the compound thickener on the texture coefficient,paste-holding rate and sensory score of the sauce packets were examined;the effects of disodium 5’-flavoring nucleotide and yeast extract on the sensory score of the sauce packets were examined.0.12%,and 2%of yeast extract.And the seasoning sauce package using this optimized formulation met the commercial sterility requirements.