Drying and Properties of Solid Residue from Guava (Psidium guajava) Pulp Processing

Edna Regina Amante,Isabela Da Silveira,Vanessa Maria Gervin,Salete Maria De Olinda Carvalho Farias

doi:10.31487/j.jfnm.2020.02.07

Abstract

The solid residue from pulp production of guava (Psidium guajava) represents around 30% of the raw material. The drying of this residue on drier’ trays at 45, 50, 55, 60, 65 and 70 °C was investigated. After drying, the material was ground in one of two types of mills: a knife or a hammer mill. Guava flour samples were characterized according to their water absorption capacity (WAC), oil holding capacity (OHC), emulsifying and foaming properties, lycopene, total carotenoids and phenolic compounds. The drying curves show typical behaviour and five mathematical models (two-term exponential, Henderson and Pabis, diffusion approximation, Page and logarithmic) were constructed. Of the models tested for the temperatures applied in the experiment, only the Henderson and Pabis model, when adjusted to the experimental data obtained at temperatures of 45 to 50 °C did not represent the drying kinetics of the guava processing solid residue, with coefficients of determination of 0.9376 and 0.6905, respectively. The type of mill and the drying temperature influenced the phenolic compounds, lycopene and total carotenoids. The WAC was higher than the OHC for all drying temperatures, due to the high content of dietary fiber in this residue.

Highlights

In recent decades a large number of papers have demonstrated the importance of the consumption of fruit, due to the presence of functional compounds
The mean square deviation (MSD) (0.008) corroborates the finding that the diffusion approximation model gave the best fit with the data for drying at 60o C (Table 1)
The diffusion approximation model gave a good fit with the data for the guava processing solid residue dried at a temperature of 60 °C, while the Page model provided the best fit with the data for the samples dried at 65 °C

Summary

Introduction

In recent decades a large number of papers have demonstrated the importance of the consumption of fruit, due to the presence of functional compounds. The seeds, peel and fruits with low added value for fresh consumption can represent approximately 50 % of the processed fruit and these can be transformed in new products. This potential use is dependent on the characterization of the material properties [1]. Of the great variety of fruits appreciated and exploited worldwide, guava (P sidium guajava) is one of the most complete and balanced due to its nutritional value, low-calorie content and high fiber, bioactive compounds and vitamin C contents [2, 3]. China, Thailand, Pakistan and Mexico are the world’s largest guava producers [4]

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Conclusion