Effects of konjac glucomannan on the long-term retrogradation and shelf life of boiled wheat noodles

BACKGROUND Starch retrogradation and moisture migration of boiled wheat noodles (BWNs) result in quality deterioration and short shelf life. The objective of this research was to investigate whether konjac glucomannan (KGM) could improve the quality of BWNs and further establish the shelf-life prediction model. RESULTS The moisture distribution, recrystallization, and thermal properties of BWNs during refrigerated or ambient temperature storage were determined. Low-field nuclear magnetic resonance data showed that KGM addition induced left-shifts of T-21 and T-22 values, indicating that KGM limited the mobility of bound and immobile water among noodle matrices. X-ray diffraction spectra revealed that KGM did not change the crystal patterns of BWNs but could inhibit the starch recrystallization after refrigerated storage. The T-p and Delta H values of retrograded samples notably (P < 0.05) decreased with the increase of KGM addition, suggesting the hinderance of starch retrogradation behavior by KGM. The shelf life of BWNs was predicted by accelerated storage test combined with the Arrhenius equation. The present data displayed that the predicted shelf life of vacuum-packed and sterilized BWNs with 10 g kg(-1) KGM at 25 degrees C was 733 days, 2.4-fold that of the control group. CONCLUSION BWNs with KGM addition could inhibit starch retrogradation and improve the storage stability, consequently promoting noodle quality. (c) 2021 Society of Chemical Industry.