Tidjani Amza

Delineating the protein changes in Asian noodles induced by vacuum mixing.

In this study, the effect of vacuum mixing on Asian noodle qualities was investigated based on protein components changes and gluten formation. The results showed that the proportion of salt-soluble proteins decreased in vacuum mixed noodles while alcohol and alkali soluble proteins increased. The free sulfyhydryl content decreased significantly (P<0.05) in low protein (LP) noodles while slight and not significant (P>0.05) decrease was detected in high protein (HP) samples. Remarkable protein aggregates were observed in non-reduced SDS-PAGE patterns for LP noodles. The changes in secondary structure were reflected by the increase in α-helix and β-sheet as well as the decrease in β-turns. Furthermore, vacuum mixing conferred a more continuous and compact microstructure to both HP and LP noodle sheets as well as an increased breaking force and extensibility. In addition, less deterioration in noodle structure and water migration was observed by magnetic resonance imaging (MRI) for vacuum mixed samples during storage.

Quality characteristics, structural changes, and storage stability of semi-dried noodles induced by moderate dehydration: understanding the quality changes in semi-dried noodles.

Based on the critical water content (for noodle deterioration) concluded previously, high-temperature-short-time (HTST; 105-135°C) and medium-temperature-long-time (MTLT; 45-75°C) dehydrations were introduced in this study to produce semi-dried noodles. The effects of HTST and MTLT on the quality parameters of semi-dried noodles, as well as noodle structure, storage stability, and changes in starch and protein components were thoroughly investigated. Differential scanning calorimeter (DSC) and birefringent analysis presented few starch gelatinization (approximately 30%) in HTST dehydrated noodles. Scanning electron microscopy (SEM) images showed more compact noodle surface, with uniform pores in the cross section, probably due to enhanced protein-starch combination after HTST dehydration. Meanwhile, HTST induced protein polymerizations in semi-dried noodles, mainly by -SH-S-S interchange, and resulted in significantly (P<0.05) reduced cooking loss. Furthermore, HTST noodles showed higher microbial and color stability. Shelf-life of dehydrated samples at 120°C was extended to 5days from 1day of the control.