Effect of modified manufacturing procedure on the overall quality attributes and safety of Kishk

Abstract

The traditional manufacturing method of Kishk involves a daily addition of plain yoghurt to Bourghul (5:1 ratio), followed by heavy handling during the 5-day period of uncontrolled fermentation. In order to improve quality, safety and yield losses, a modified procedure with a single addition of strained yoghurt (Labneh), in a 3:1 ratio, was investigated. The physico-chemical, microbiological and sensory characteristics of both Kishk products were assessed during five days of controlled fermentation (RT: 23- 25 °C; RH: >85%). Green and dried modified-Kishk were of similar quality characteristics when compared to traditional ones. Moisture content was lower in traditional (63 %) compared to modified (66 %), whereas titratable acidity was higher in modified Kishk (1.22 against 1.02 %). Peroxidation (PV = 0; TBARS = 0.2 mg MDA/Kg), and lipolysis (AV max 3.48 %) were always in the acceptable ranges. Pathogenic bacteria (E. coli, Salmonella spp., L. monocytogenes, S. aureus) were not detected neither in green nor in dried Kishk. Sensory analysis revealed a harder texture, higher viscosity and higher scores for appearance, odor and overall acceptability in green Modified-Kishk. After drying into fine powder, Modified-Kishk showed improved nutritional, organoleptic and physical quality attributes. The modified end-product can conveniently be safely produced on an industrial scale with optimum conditions.