Effects of sterilization process on the physicochemical and nutritional properties of liquid enteral formula

Abstract

Ultra-high temperature (UHT) and retort processes are widely applied in the sterilization of liquid enteral formulae. This study investigated the effects of sterilization process on the physicochemical and nutritional properties of a liquid enteral formula. An ingredient mixture was sterilized by either UHT processing at 150°C for 5 s, or retort processing at 121°C for 10 min (retort A) or 121°C for 40 min (retort B). In vitro assays showed less protein modification in the UHT formula than in either retort formula. In vivo assays also demonstrated that net protein utilization was greatest with the UHT formula, and cecal nitrogen and ammonia concentrations in rats fed the UHT formula were lower than in rats fed either retort formula. These results indicate that the sterilization process affects the protein quality of the formula as well as the intestinal environment of rats fed the formula.