Effect of packaging materials and storage temperature on water status, mechanical and thermal properties of black garlic

Abstract

Abstract We examined the effects of the packaging materials [polyethylene terephthalate bottles (PETB), Kraft paper bags (KPB) and aluminum-laminated polyethylene bags (ALPB)] and storage temperatures (4 and 20 °C) on the chemical composition, water status and mechanical and thermal properties of black garlic after 90 days of storage. We found that ALPB retained the highest levels of 5-hydroxymethylfurfural, total sugar and reducing sugars at the same temperature while PETB retained the textural properties of the garlic. Water loss and migration were serious defects in KPB and PETB at 20 ℃. The initial decomposition temperature was highest for KPB while the glass transition temperature was highest for ALPB. The samples stored in ALPB could easily be differentiated from the others using an orthogonal partial least squares-discriminant analysis model and this gave a high predictive power of 98.9 %. Taken together, low temperatures and ALPB most effectively maintained the integrity of the black garlic.