Tarhana is known as a fermented cereal product made traditionally from wheat flour and yoghurt. As a novelty, kefir was used as substitute for yoghurt in tarhana production partially and completely to investigate the effects on fermentation activity, nutritional, sensory and rheological properties of tarhana. Addition of kefir increased the fermentation activity as raise in acidity values was observed compared to tarhana samples prepared with yoghurt. Regarding dry tarhana samples, the highest acidity degree, protein, ash and phenolic contents were detected in samples prepared with 100% kefir. Counts of LAB groups (M17 and MRS agar) of tarhana enriched with 100% kefir was higher than that of other tarhana samples during the fermentation period. Moreover, kefir affected the scores of sensory properties of tarhana soups. Tarhana soups prepared with kefir gave the highest scores for mouth feel, odour and consistency attributes. Tarhana soup prepared with 50% yoghurt and kefir showed the lowest viscosity probably due to synergistic effect on starch hydrolysis by bacterial population from both ingredients. These results suggest that replacement of yogurt with kefir in the formulation of Tarhana may enhance some properties of the soup.

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Purpose β-carotene, found naturally in many foods, has been widely used as a colourant in various products. The aim of this study is to optimize the production of β-carotene by Blakeslea trispora using bug-damaged wheat as the main nitrogen and carbon source. Design/methodology/approach Response surface methodology (RSM) has been used to determine the optimum concentrations of media components for the maximum β-carotene production. β-carotene concentration was determined quantitively using a spectrophotometric method. Findings A full quadratic model fit the data best for β-carotene production with a high R2 value (0.999). Using optimized media increased the production of β-carotene by B. trispora DSM-2387 and B. trispora DSM-2388 to a higher level (250.407 mg/l) than the control medium (72.195 mg/l). Originality/value This study showed that bug-damaged wheat, an agro-industrial waste having low economical value, may be used as a valuable substrate for microbial production of β-carotene, a natural food colourant possessing high economical value.

Biofilm formation in food processing environment and within equipment increases the risk of product spoilage and contamination with pathogens. Cleaning-in-place (CIP) operations are useful in removing soils and in sanitizing processing equipment, including eliminating biofilms. However, CIP is a resource-intensive process, particularly in the usage of chemical detergents, heat, and sanitizers. The current study was initiated to investigate the feasibility of integrating ozone into CIP operations to facilitate the elimination of Pseudomonas biofilm, with the long-term goal of decreasing the dependance on conventional cleaning and sanitizing reagents. To investigate integrating ozone into CIP, a robust biofilm of Pseudomonas fluorescens was developed on a pilot-scale food processing equipment after 2 days of incubation in 10% skim milk (skim milk-water mixture, 1:9 v/v) under stagnant conditions, followed by additional 5 days of circulation while feeding 10% fresh skim milk. CIP was applied using water prerinse at 22–25°C, alkaline cleaning with 0.2% potassium hydroxide at 50°C, and a final water rinse. These CIP operations reduced planktonic cell populations below the detection method’s limit but did not fully remove P. fluorescens biofilm from either smooth or rough surfaces of the processing equipment. When the CIP process was followed by application of an aqueous ozone step (10 ppm for 10 min), the treatment reduced biofilm cell population, on smooth and rough surfaces, below the recovery method’s detection limit (0.9 and 1.4 log CFU/ 100 cm2, respectively). These findings demonstrate the utility of ozone-assisted CIP in eliminating microbial biofilms on processing equipment, but further research is needed to optimize the use of cleaning agents and the application of ozone.