Sorbitol minimizes calcium carbonate scale generation while maintaining the disinfection effect of heated scallop-shell powder for fresh produce

Abstract

Scallop shells subjected to heat treatment exhibit antimicrobial activity, and heated scallop-shell powder (HSSP) has recently been reported to be effective for disinfecting food. However, because the main component of these shells is calcium oxide, there is a problem that scales of calcium carbonate (CaCO 3 ) become established on the surface of equipment used for food processing. In this study, we thus investigated whether the addition of sugar to HSSP slurry suppressed CaCO 3 scale generation and whether the sugar-supplemented HSSP could be applied to the disinfection and preservation of fresh lettuce. The results showed that glucose, sucrose, and sorbitol could suppress the scale generation in HSSP slurry. However, glucose and sucrose decreased the antibacterial activity of HSSP. Since the addition of sorbitol did not affect the antibacterial activity of HSSP slurry, it was used for subsequent experiments because of its low bioavailability. Sorbitol effectively suppressed scale formation by dissolving it before the addition of HSSP. The disinfection and preservative effects of sorbitol-supplemented HSSP (S-HSSP) treatment on lettuce did not decrease compared with those upon HSSP treatment and were almost equal to or higher than those of sodium hypochlorite treatment at 200 mg/l. The addition of sorbitol solved the major problem of scale generation by HSSP containing CaO, which contributes to expansion of usage of heated shell powder, such as HSSP, in food processing.