Spray drying of avocado pulp using the seed as an adjuvant

Abstract

Avocado, a native fruit from Mexico and Central America, is found in almost all tropical countries and consists of peel, pulp and seed. Avocado is a complementary food containing many lipophilic phytochemicals and bioactive compounds that may confer health benefits. The avocado seed represents 10% to 25% of its entire weight, depending on the fruit variety. It is a compelling source for creating new products because it is one of the best sources of dietetic fibre, with substances like fatty acids and antioxidants. However, in 2017, about 42,600 t of seeds were discarded in Brazil. Moreover, there are other problems and limitations to the use of avocado due to its low acidity and high perishability under environmental conditions. Therefore, it is necessary to employ conservation techniques to increase its shelf life. The avocado drying process has been studied, and the results show that avocado powder can potentially be used in the food, pharmaceutical and cosmeceutical industries, among others. This study aimed to assess the drying process of avocado pulp in a spray dryer, using the flour of its seed as an adjuvant to add value to that residue. The influence of outlet air temperature (90 °C – 110 °C) and seed flour concentration in the drying paste (0.0%–3.0% w/w) on the process yield and moisture content were evaluated using a factorial design. Furthermore, the paste and powders were chemically and physically characterised. The best drying condition was under an outlet air temperature of 110 °C and 3.0% seed flour concentration. That process combined the highest process yield (50%) with a low-moisture level of 1.25% and a low-water activity powder of 0.29. The use of the seed favoured the process yield compared with maltodextrin, showing that seed flour can be employed as an adjuvant in drying. The flowability of the powder was classified as cohesive, and the instant properties were poor. However, the avocado powder showed a similar protein, ash, lipids and carbohydrates content compared to the drying paste, making the product as nutritious as the fresh fruit. Additionally, it is a product with a high fibre content (10.47 g/100 g). The results suggest that avocado powder can be used as an ingredient for developing healthy food formulations, such as confectionery and bakery products. Special attention must be given to masking any bitter taste that may arise. © 2022