| Fresh rice noodles have emerged as a popular convenience food in recent years,favored by consumers for their rich nutrition,smooth taste,and convenient consumption.With a broad market prospect,fresh rice noodles are faced with the challenge of high moisture content and a high starch base,which make them prone to rejuvenation during storage,leading to quality degradation and shortened shelf life.This issue has become a bottleneck problem hindering the development of the fresh rice noodles industry.Therefore,it is imperative to find effective methods to inhibit the rejuvenation of rice noodles.In this paper,we aim to screen special compound anti-retrograding agents that are suitable for fresh rice noodles and explore their anti-retrograding mechanism.Our goal is to develop a control scheme for fresh rice noodles that is suitable for industrial production,cost-effective,and exhibits a significant anti-rejuvenation effect,thereby promoting the industrial development of the rice products industry.In this study,the effects of five different types of anti-retrograding agents,namely tea polyphenols,erythritol,kelp polysaccharide,sucrose fatty acid ester,and pyrodextrin,on the cooking and eating quality,as well as storage stability,of fresh rice noodles were investigated.The results revealed that sucrose fatty acid ester significantly increased the hardness and breakage rate of fresh rice noodles.Tea polyphenols had a pronounced impact on the color and flavor of fresh rice noodles,while the other three anti-retrograding agents showed no significant effect on the physicochemical and sensory quality of fresh rice noodles.During the storage period,kelp polysaccharide exhibited no significant effect on the retrogradation of fresh rice noodles,whereas erythritol and pyrodextrin demonstrated significant improvement in storage stability.For instance,after 35 days of storage,the control group showed a 31.13%increase in cooking loss,a 20.19%increase in breakage rate,a 50.16%increase in hardness,a 7.25%increase in short-range order degree,and a 14.69%increase in relative crystallinity.However,the addition of erythritol and pyrodextrin resulted in only a 15.43%and 15.01%increase in cooking loss,and a 16.44%and 15.24%increase in breakage rate,respectively.Furthermore,erythritol and pyrodextrin effectively improved the cooking quality of fresh rice noodles,with a hardness increase of 13.06%and 18.57%,a short-range order increase of 0.049and 0.054,and a relative crystallinity increase of 13.31%and 13.29%.Importantly,erythritol and pyrodextrin were found to significantly inhibit long-term retrogradation of fresh rice noodles.In conclusion,erythritol and pyrodextrin are suitable as special anti-retrograding agents for the production of high-quality fresh rice noodles.Secondly,the effects of different preparation conditions on the microstructure and properties of pyrodextrin were investigated.The experimental results revealed that pyrodextrin prepared under acid heat conditions exhibited a smaller molecular weight,higher branching degree,and shorter chain length compared to pyrodextrin prepared under dry heat conditions.The average molecular weight could be reduced to 3×10~5g/mol,the branching degree increased to 13.70%,and the chain length reduced to 5.76.Additionally,the pyrodextrin particles exhibited a higher content ofβ-1,2 linkages compared toβ-1,4 andβ-1,6 linkages,indicating a more branched structure.Furthermore,the effects of pyrodextrin prepared under different conditions on the quality and storage stability of fresh rice noodles were investigated,and the anti-retrograding mechanism was explored.The experimental results demonstrated that the hardness of fresh rice noodles increased by only 14.28%after 35 days of storage,which was significantly lower than the 35.23%increase observed in the fresh rice noodles group and the 50.16%increase in fresh rice noodles group after the same storage period.The increase in cooking loss of fresh rice noodles was also reduced to 15.13%,which was significantly lower than the 21.37%observed in the commercially available fresh rice noodles group.Additionally,the broken strip rate only increased by 13.40%,which was significantly lower than the 20.95%increase observed in the commercially available fresh rice noodles group.In conclusion,pyrodextrin prepared by heating for4 hours under acid heat conditions is suitable as an anti-retrograding agent for the preparation of fresh rice noodles.Finally,the erythritol that was screened previously was combined with the pyrodextrin prepared through a 4-hour acid heat condition,and the effects of different compounding ratios and dosages on the quality and storage stability of fresh rice noodles were investigated.The experimental results showed no significant differences between the control group and the experimental group in terms of texture characteristics,cooking characteristics,crystallization characteristics,and thermal characteristics of rice noodles at 0 days of storage.However,after 35 days of storage,the quality of fresh rice noodles deteriorated.Specifically,the hardness of fresh rice noodles increased by39.17%,from 1035.72 g to 1441.39 g.Among the experimental groups,the compound group with 1%erythritol and 3%pyrodextrin(C1J3),2%erythritol and 2%pyrodextrin(C2J2),and 3%erythritol and 1%pyrodextrin(C3J1)showed increases in hardness by10.89%,9.69%,and 13.00%,respectively.In terms of hardness indexes,the anti-retrograding effect was found to be highest in the C2J2 group,followed by C1J3,and then C3J1.The cooking loss of the fresh rice noodles group increased significantly from10.24%to 21.67%,with an increment of 21.85%.However,the groups with different anti-aging agents showed no significant differences in cooking loss increment,ranging from 15%to 16%.The breakage in the fresh rice noodles group started from the 14th day,and the breakage rate increased from 0%to 21.67%with the increase in storage time.The C2J2 group had the lowest increase in breakage rate,with a 13.33%increment after 35 days of storage,among all experimental groups.The water migration of the experimental group with the compound anti-aging agent changed minimally during the storage process,indicating that the compound anti-aging agent can strengthen the water binding force of fresh rice noodles during storage,thus reducing the quality degradation caused by water migration.TheΔH of the marketable fresh rice noodles increased from1.42 J/g to 4.65 J/g during storage,while theΔH of the C1J3 group increased from 1.27J/g to 2.97 J/g.The crystal quantity of fresh rice noodles in the C1J3 group was significantly lower than that in the control group,indicating lower degree of retrogradation.The results of sensory evaluation showed that at 0 days of storage,the total score of the commercial fresh rice noodles group did not differ significantly from that of the experimental groups.However,when the storage time reached 35 days,the total sensory score of the C1J3 experimental group was significantly higher than that of the commercial rice noodles group. |
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