Investigating the changes of texture, physicochemical properties, microbial diversity, and volatile compounds of quinoa fresh noodles during storage time

Abstract

AbstractBackgroundQuinoa was suggested to substitute in noodles with positive effects of cardiovascular disease, metabolic, and gastrointestinal systems. However, quinoa fresh noodles (QFN) were hard to preserve but constrain industrial production. The deteriorative changes in the quality and relative parameters of QFN at 25 ± 1°C are lacking and needed to investigate.FindingsIn this study, QFN was sampled every 12 h at 25 ± 1°C, and found that the total plate count exceeded safety limit (5 log10 CFU/g) in 24 h. Bacillus, Staphylococcus, Aspergillus, and Filobasidium were the dominant spoilage microorganisms, where Bacillus was significantly increased and accounted over 90% of bacteria after spoilage. The volatile compounds changed significantly, where aldehydes decreased from 58.25% to 30.09%, while easters and alcohols increased from 2.29% to 14.84%, and 7.78% to 20.28% separately. With increasing of storage time, the water content and water activity decreased. Besides, strongly bound water decreased from 12.51% to 7.63%, weakly bound water and free water increased. The color of QFN turned to dark and red, where a value increased from 2.11 to 3.82, while L value decreased from 75.20 to 64.56. pH of QFN also decreased during storage. The quality index of QFN was qualified with decreased texture properties (hardness, springiness, and chewiness) and significantly increased cooking loss rate (8.65%–12.74%) and cooked broken rate (0%–26.67%).ConclusionsThe storage time of QFN was 24 h at 25 ± 1°C. The textural changes and certain indexes changed significantly after spoilage. And relative indexes of QFN qualities presented significant correlation with microorganisms.Significance and NoveltyBacillus in QFN may contribute significant changes in spoilage. The correlation analysis figured out the possible reasons for qualities changes of QFN.