Engineering factors in single‐cell protein production. II. Spray drying and cell viability

Abstract

One important economical method for producing singlecell protein is to spray dry the cultured cells. This study presents some preliminary data on the effects of spray drying on cell viability. Under conditions similar to those for the production of spray-dried milk, 4-5 log cycles destruction occurred. The results indicate that the activation energy for thermal destruction of yeast was reduced from the normal heat treatment value of 84 kcal/"K mole to about 38 kcal/"K mole.

Survival of Lactic acid Bacteria during Microwave Vacuum-drying of Plain Yoghurt

“…Eqn [1] where a w = water activity; m = moisture content (kg/kg solid); m 0 = 'monolayer' moisture content (kg/kg solid); C 1 = GAB constant related to 'monolayer' properties; and C 2 = GAB constant related to multilayer properties. The influence of temperature on the GAB parameters (m 0 , C 1 and C 2 ) was described by the following equations which are similar to the Arrhenius equation.…”

“…In the case of beneficial microorganisms, however, their survival is rather meaningful and important. Such survival has been studied by several authors with respect to either the maximum microbial yield of a dried product or the optimum drying conditions (1)(2)(3)(4). The viable cell number of lactic acid bacteria in a yoghurt powder is an important quality factor and a good index for evaluating the degree of damage exerted during drying (4).…”

Spray Drying Yogurt Incorporating Hydrocolloids: Structural Analysis, Acetaldehyde Content, Viable Bacteria, and Rheological Properties

“…Because of the rapid drying rate and the short residence time in the dryer, thermal damage to the constituent microorganisms is small (Labuza et al 1970). Unfortunately, the drying process may affect other quality parameters of the product.…”

Optimization of brewer’s yeast spray drying process

“…Spray drying was reported as an appropriate preservation method for yeast and other microorganisms (Kim & Bhowmik, 1990;Labuza, Le Roux, Fan, & Tannenbaum, 1970;Wan-Yin, Shing-Yi, & Mark, 1994). The effect of spray drying process variables over final moisture and biological or biochemical activity of dehydrated products was also amended (Labuza et al, 1970;Luybe, Liou, & Bruin, 1982;Ramírez, Salgado, Rodríguez, & García, 1998;Ré, 1998).…”

“…The effect of spray drying process variables over final moisture and biological or biochemical activity of dehydrated products was also amended (Labuza et al, 1970;Luybe, Liou, & Bruin, 1982;Ramírez, Salgado, Rodríguez, & García, 1998;Ré, 1998). More specifically, Rodréiguez (1998, 2000) reported how spray drying process variables and processing aids might improve dried brewerÕs yeast viability.…”