Effects of alternating magnetic field on freezing of minimally processed guava

The effects of alternating magnetic fields (AMF) on the freezing kinetics and quality parameters of minimally processed guava were investigated. The freezing process parameters including magnetic field intensity (2.4–8.8 mT) and cube size (2–4 cm) were optimized for fresh-cut guava cubes using the Response Surface Methodology technique. A comparative evaluation of freezing kinetics obtained for guava cubes frozen under different magnetic field intensities (2.4, 5.6, and 8.8 mT) was drawn with respect to the control samples. The two-factor, three-level Box and Behnken design suggested that the samples of size 4 cm, treated with a magnetic field intensity of 7.02 mT yielded the optimum freezing characteristics for which the values of phase change time, drip loss, and firmness were 77 min 35 s, 4.97%, and 1.34 N respectively. Significant reductions were observed in phase transition times of frozen guava cubes amounting for 62.4% (4 cm), 44.71% (3 cm) and 27.36% (2 cm) under AMF intensity of 8.8 mT, 5.6 mT and 8.8 mT respectively. Hence, AMF assisted freezing has potential implications in terms of preservation of product quality and efficient energy utilization in the food processing industry.