The effects of flaxseed (Linum usitatissimum) flour (FF) and packaging conditions on microbial counts, lipid stability and cooking quality were determined for fresh pasta stored 7 weeks at 4C. Fresh pastas made from semolina or semolina blended with 15% (w/w) FF (FF‐pasta) were packaged in metallized bags under three conditions: ambient air, nitrogen and vacuum. Packaging conditions did not affect aerobic or anaerobic plate counts. Mold and yeast counts were lower for pasta packaged under vacuum than under ambient air or nitrogen. Compared with traditional fresh pasta, FF‐pasta had lower microbial counts during storage. Free fatty acid content in FF‐pasta increased from 1.9 to 2.4% during storage. Lipid oxidation was lowest with vacuum‐packaged pasta. Packaging conditions had little or no effect on cooking quality. Compared with traditional pasta, FF‐pasta had lower cooked firmness and cooking loss. Cooked firmness was found to decrease only during the first week of storage; no further decrease occurred during the subsequent weeks. PRACTICAL APPLICATIONS This research would have practical applications to the fresh, refrigerated pasta industry. Although limited in scope, the results indicate that flaxseed flour (FF) has some bacteriostatic and fungistatic activity that may be useful in extending shelf life of fresh, refrigerated pasta/noodle products, and that further research to improve and maintain the cooking quality of FF‐pasta during storage is needed.

Flaxseed (Linum usitatissimum L.) is an emerging food ingredient because of its several health benefits. Research was conducted to determine the effects of semolina, hydration level during extrusion and flaxseed flour concentration on the physical and cooking characteristics of freshly extruded pasta. The appearance of fresh pasta reflected the appearance of the ingredients. Fresh pasta became darker and redder as flaxseed flour concentration increased. Flaxseed flour did not affect cooking loss or water absorption during cooking of fresh pasta. However, flaxseed flour reduced the cooked firmness of fresh pasta by decreasing the dough strength. The cooked firmness of fresh pasta containing flaxseed flour was improved by using a semolina that makes a strong dough rather than a weak dough, and by extruding at a low (29%) compared to high (31%) hydration level. PRACTICAL APPLICATIONS Research results reported in this article would be useful in the development of a processing protocol for fresh pasta containing flaxseed flour and possibly other nontraditional ingredients. The results provide support for the need to use a strong dough‐forming semolina and to extrude the semolina–flaxseed flour mixture at a low hydration level (29%) in order to produce a fresh pasta that has desirable cooking/cooked properties.

Proteases are enzymes that hydrolyze peptide bonds and, therefore, lead to the disassembly of proteins. Commercially these are extremely important as more than 60% of the total enzyme market is made up of proteases, out of which 40% are acid proteases. The objective of this study was to compare the available standard strains, Rhizopus oligosporus MTCC-556, Rhizomucor miehei MTCC-546 and Aspergillus awamori MTCC-548, which were examined for the production of acid protease by submerged fermentation. Aspergillus awamori showed maximum proteolytic activity and was selected for further optimization studies. During the course of study the medium was altered. Effect of different carbon sources (lactose, sucrose, and combination of these two in same ratios and glucose) on the proteolytic activity of acid protease produced by A. awamori MTCC 548 was studied and it was found that glucose showed highest proteolytic activity. The effect of various concentrations of glucose was also studied on the acid protease production and its 1% concentration was found to be optimum; it showed proteolytic activity of 0.11 U/ml. Among the different nitrogen sources, such as casein, peptone, skim-milk powder and peanut meal, the peanut meal was found better for enzyme production. Peanut meal, with a concentration of .2% in the medium, increased proteolytic activity up to 0.218 U/ml. The effect of additives, such as Tween-80 and chemicals like CaCl2 and skim-milk powder, was also studied and it was found that 0.05% Tween-80 was effective in enzyme production and a proteolytic activity of 0.225 U/ml was obtained. The enzyme extract was separated in the form of supernatant by using centrifuge and the enzyme activity was analyzed by Anson’s method using a spectrophotometer. The enzyme produced was recovered by using a saturated solution of 80% ammonium sulphate and protein content was determined by Lowery method using a spectrophotometer. It was found that the specific enzyme activity was increased from 0.155 U/mg proteins to 0.174 U/mg proteins showing a purification fold by a factor of 1.12 by using 80% saturated ammonium sulphate.