Hot air convective and infrared dried probiotic red grape pomace: phytochemical and physico-chemical properties, cell viability and the in vitro digestion of anthocyanins

• The red grape pomace was inoculated with Lactobacillus casei ssp. paracasei and dried. • Higher anthocyanin content was observed in infrared powder. • Both powders showed a satisfactory cells viability. • The in vitro digestion highlithed an increase in intestinal phase for anthocyanin. • The powders showed a good flowability and cohesiveness. Two drying methods were selected (hot air convective (CD) and infrared drying (IR)) for red grape pomace (GP) inoculated with Lacticaseibacillus casei ssp. paracasei . A higher moisture content was found in CD powders, influencing both the antioxidants content and technological properties. The anthocyanin content in IR powder reached 388.71±1.47 µg cyanidin-3-glucosides equivalents (C3G)/g dry weight (DW) when compared with 154.17±1.01 µg C3G/g DW in CD powders. The cell viability reached approximatively 8.00 log/g DW and 7.00 log/g DW in IR and CD powders, respectively. The results showed an increase in intestinal phase for anthocyanin and a cells viability of 6.5 log CFU/g DW in CD powder. The powders showed good flowability and cohesiveness, which increased during storage. A higher porosity was found in CD powder of 68.48 ± 6.04% compared with 60.27 ± 6.25% for IR powder. A higher water holding capacity was found for IR samples, with no significant differences in oil holding and swelling capacities. The polyphenolic content increased during storage for 30 days at 25°C of both powders, with a higher percent in CD powders, especially for anthocyanin’s. Both powders showed a reddish-yellowish color, with a mild whitening and an intensification of red and yellow color during storage.