Improvement of physicochemical and nutritional qualities of frozen Marionberry by vacuum impregnation pretreatment with cryoprotectants and minerals

Vacuum impregnation (VI) with cryoprotectants and minerals was used as a pretreatment to freezing for improving quality of and introducing nutraceuticals into frozen Marionberry. High fructose corn syrup (HFCS) and high methoxyl pectin (HMP) were used as cryoprotectants, and calcium gluconal (CG) and/or zinc lactate (ZL) were integrated into the solution as nutraceutical ingredients. The VI process consisted of a 15 min vacuum at 50 mmHg, following an atmospheric pressure restoration for 30 min. The VI pretreatment increased the maximum compression force of frozen-thawed Marionberries 45% to 137%, and reduced the drip loss 28% to 48% depending on the specific VI condition. Calcium provided additional benefits to the texture quality, and zinc improved colour stability of frozen-thawed berries. In addition, the VI pretreatment increased the Dietary Reference Intake (DRI) of calcium and zinc to about 11% and 23% in 200 g of frozen-thawed berries, respectively.