Effect of freezing rates and freeze-thaw cycles on the texture, microstructure and pectic substances of mango.
Charoenrein S., Owcharoen K.
Author Affiliation: Department of Food Science and Technology, Faculty of Agro-Industry, Kasetsart University, Bangkok 10900, Thailand.
International Food Research Journal 23 : 613-620
Abstract : The objective of this study was to investigate the effect of freezing rates and freeze-thaw cycles on the texture, microstructure and pectic substances (i.e. alcohol insoluble solids (AIS), total pectin (TP), water soluble pectin (WSP) and ammonium oxalate soluble pectin (ASP)) of mango. With repeated freeze-thaw cycles, the WSP, ASP, and drip loss demonstrated a tendency to increase whereas firmness decreased. Although freezing reduced the firmness, fast frozen samples had the highest firmness values. A microstructure analysis showed that the cell walls of the frozen samples were destroyed by ice formation leading to cell shrinkage and collapse. The degradation of the cell walls was more obvious for slow frozen samples than for the fast and medium frozen samples. This study shows that freezing rates and repeated freezing and thawing have an obvious impact on the quality of soft fruits such as the ripe mango.