|YU, YUANSHAN - Guangdong Academy Of Agricultural Sciences|
|XU, YUJUAN - Guangdong Academy Of Agricultural Sciences|
Submitted to: Drying Technology: An International Journal
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/10/2016
Publication Date: 12/1/2016
Citation: Yu, Y., Jin, Z.T., Fan, X., Xu, Y. 2016. Osmotic dehydration of blueberries pretreated with pulsed electric fields: Effects on drying rate, and microbiological and nutritional qualities. Drying Technology: An International Journal. doi: 10.1080/07373937.2016.1260583.
Interpretive Summary: Microbiological and nutritional qualities are important for osmotic dehydrated blueberry fruits. In this study, fresh blueberries pretreated with pulsed electric fields (PEF) before osmotic dehydration. The results show that PEF pretreatment reduced the dehydration time by 72 hours and enhanced the microbiological quality of dried fruits without affecting their nutritional quality. This study demonstrates that PEF pretreatment could be a useful approach to reduce production cost.
Technical Abstract: Fresh blueberries were treated by pulsed electric fields (PEF) at 2 kV/cm before osmotic dehydration in 70% sugar syrup. The changes in water loss, solids gain, populations of native microorganisms, antioxidant activity, contents of anthocyanins, predominant phenolic acids and flavonols, and total phenolics in blueberries were investigated after PEF pretreatment and during osmotic dehydration at 40 degrees C. Compared with non PEF-pretreated blueberry samples, PEF-pretreatment reduced the osmotic dehydration time of blueberry samples from 120 h to 48 h at target moisture content (3.0 g/g initial dry matter). No significant differences (P>0.05) in total phenolics, antioxidant activity, anthocyanins, and predominant phenolic acids and flavonols were observed between the PEF-pretreated and non PEF-pretreated blueberry samples. The PEF pretreated blueberry samples had lower microbial populations than those which were not subjected to PEF pretreatment. Regardless of pretreatment, decreases in anthocyanins, predominant phenolic acids and flavonols, total phenolics, and antioxidant activity in blueberries were observed during the osmotic dehydration process. The results demonstrate that PEF pretreatment significantly accelerated the drying rate and enhanced the microbiological quality of blueberries without affecting their nutritional quality.