Effect of partial drying intensity, frozen storage and repeated freeze-thaw cycles on some quality attributes of dehydrofrozen quince fruit

The present study investigated the effect of multi-freeze-thaw cycles on thawed water exudate, final water content, color features, and polyphenolic contents of frozen and dehydrofrozen quince fruit. Quince pieces were predried at 40 °C and 3 m/s, until specific final water contents: 2, 1, and 0.3 g H 2 O/g db, then, frozen at − 18 °C and stored during 6 months. Monthly, quinces were thawed at 20 °C to perform quality analyses: treated quinces had remarkable water retention, and no significant difference between values over storage time has been recorded (p > 0.05). Convective pre-drying step remarkably reduces the negative impact of freezing/thawing processes and freeze-thaw cycles on quince color and guarantees its stability during frozen storage: a significant decrease of thawing impact on total color difference has been noticed for dehydrofrozen samples (3.32) compared to (12.53) for conventionally frozen ones. Finally, dehydrofreezing allows a better retention of polyphenols content, during frozen storage. Fruits quality, with high water content, such as quinces may be compromised by freezing and frozen storage. Tissue damage occurs as ice accrues and concentrates soluble solids. Convective pre-drying can remove some of the available water, which reduces ice formation during freezing and subsequently storage. This piece of work has proved the potential use of convective air drying before freezing to reduce the negative impact of freezing/thawing processes and freeze-thaw cycles on quince quality and guarantees its stability during storage. These fruits marketability is highly correlated with their textural quality in addition to their color properties and bioactive components. Dehydrofreezing is recommended for better quince fruit quality preservation during storage. Thus, it may be a commercial method to reduce shipping costs and fruits storage.