Effect of steam blanching on lycopene and total phenolics in pink guava puree industry by-products

Lycopene and total phenolics of pink guava puree industry by-products (refiner, siever and decanter)were evaluated after steam blanching at selected temperatures and times. Lycopene content was in the order of decanter siever refiner (7.3, 6.3 and 1.5 mg/100 g, respectively), and the content of total phenolics was in the order of refiner siever decanter (4434.1, 2881.3 and 1529.3 mg GAE/100 g, respectively). Regression coefficients for temperatures (x1) and times (x2) from multiple linear regression models of siever and decanter showed significant (p 0.05) negative relationships with lycopene (y1) and total phenolics (y2). Nevertheless, lycopene content in decanter increased significantly about 13% from the control when steam blanching at 60 °C for 20-60 min. More than 27% of total phenolics were lost in blanched refiner. Regression analysis revealed the increasing loss of lycopene and total phenolics during steam blanching could occur when increasing in temperature and time.