ELECTROMAGNETIC RADIATION-BASED DRY BLANCHING OF RED BELL PEPPERS: A COMPARATIVE STUDY

摘要

Retention of water-soluble nutrients, prevention of solid loss and elimination ofnwaste water generation are some of the advantages of dry blanching. Dry blanchingnof red bell pepper (Capsicum annuum L.) slices using infrared (IR) and microwaven(MW) radiations was attempted and its performance was compared withnconventional water and steam blanching methods. Processing conditions (timenand temperature) were standardized on the basis of degree of enzyme inactivationn(peroxidase, polyphenol oxidase). Effect of blanching methods on retention ofnmicronutrients such as ascorbic acid, β-carotene and protein, besides productnshrinkage, structure and texture (shearing force) were analyzed. Water and steamnblanching were found to need lower processing time (1.0 and 1.5 min, respectively)ncompared with IR (6.0 min) and MW blanching (3.0 min). However,nMW-blanched samples retained higher amounts of ascorbic acid (94.7%). Drynblanching with IR (150C) and MW (17.5 W/g) resulted in higher retention ofnβ-carotene (103.2 and 118.6%, respectively) compared with water (60.3%) andnsteam blanching (88.3%). Dry blanching resulted in moisture loss (1–6%) andnshrinkage, perhaps resulting in higher shearing force observed in dry blanchednslices. Scanning electron micrographs indicated that method of blanching has anrole on extent of effect on cell structure.