ASABE Technical Library - Abstract

Abstract. Mexico is one of the largest producers of cactus in the globe. Prickly pear, or cactus pear fruit (Opuntia spp.) is an ancient fruit harvested from nopal species. Currently, is cultivated also in Africa and Mediterranean areas; they produce wine, juices and other prickly pear derivatives. However, prickly pears are often attacked by pests, such as Dactylopius indicus Green and Aceria cactorum. In the past years, pesticides were employed in order to avoid pests; however, due to health and environmental concerns, their use has been restricted in diverse countries. An alternative to chemical compounds is the application of heat treatments; among them, microwaves offer the advantage of volumetric and fast heating. The objective of this study was to analyze the effect of hot water (HW) or microwave-assisted hot water treatment (MWHW) on the postharvest quality of prickly pears. Fruits (Opuntia ficus-indica, cv. White or Opuntia streptacantha cv. ‘Red‘) were heated until 49 ºC, held for 4 min for all the treatments (holding time enough to kill pests). For microwave treatments, two power levels were analyzed: 350 and 500 W. After the applied treatment, fruits were cooled in water at 11ºC for 21 min. A set of fruits was left without treatment as a control. ‘White‘ variety was more affected in color and firmness than ‘Red‘ variety. Weight loss in the treated fruits was lower than in untreated fruits (p<0.05). The treatments did not affect (p>0.05) the pH (5.1-6) and total soluble solids (9.8-12ºBx) in the prickly pear juice. Microwave-assisted hot water treatment at low power (350 W) has potential to maintain the postharvest quality of prickly pears.