Phytochemical composition and in-vitro bioaccessibility of phenolics in different varieties of tamarillo (Solanum betaceum) fruits: Effect of the high-pressure homogenization and ultrasonication

Abstract

The phytochemical composition in three different varieties of tamarillo (yellow, red, and purple) cultivated in Northeast India was analysed. The pulp showed good amount of protein, fat, and crude fiber, and the pH and TSS of the tamarillos ranged from 3.70 to 3.94 and 9.6–10.2 °Brix, respectively. Vitamin C was highest in purple tamarillo and all were rich in potassium. Anthocyanins were majorly found in purple tamarillo (0.35 mg C3G/g), while carotenoids were maximum in yellow tamarillo (0.63 mg βCE/100 g). However, both anthocyanins and carotenoids pigments were found in purple and red tamarillo varieties. Through HPLC analyses, six phenolic acids were identified and among them, gallic, chlorogenic, ferulic and rosmarinic acids were the major ones. Pelargonidin-3-O-rutinoside was the major anthocyanin in purple (86.22 µg/g) and red (9.88 µg/g) tamarillo. Three different carotenoids viz. zeaxanthin, β-cryptoxanthin and β-carotene were present in all the varieties of tamarillo. High pressure homogenization and ultrasonication treatments had significant impact on the phytochemical composition. High pressure homogenization at 750 bar and ultrasound for 10 min showed higher phenolics, anthocyanins and carotenoids in the tamarillo varieties and these techniques are recommended for processing of tamarillos. The treated pulp rich in phytochemicals can be used for novel product development.

Keywords

• Tamarillo
• Biochemical analysis
• Polyphenols
• Antioxidant activity
• HPLC
• In-vitro digestion