Evaluation of food quality according to volatile compound profile

: influence of the processing in volatile compounds in apple juice

Abstract

Apples are one of the most extensively cultivated fruit in the world and the juice is an important product worldwide. Fruit aroma is a complex mixture of a large number of volatile compounds that contribute to the overall sensory quality of fruit. The majority of volatiles extracted from apples are esters and alcohols. Their synthesis in apples may be affected by pre, at, or post-harvest factors such as maturation process, temperature during the production process and apple’s storage. The aim of the project was to analyse the quality of apple juices from different processing steps according to the volatile compounds’profile, using a solid-phase microextraction followed by gas chromatography-mass spectrometry method (SPME/GC/MS). There were analyzed three different batches of apple juice production, with six samples in each batch (pulp, pulp with enzymes, juice after press, juice without aroma, concentrate and aroma). All samples were assayed for soluble solids, formol number and acidity, ash and phosphor content as well as the profile of volatile compound, using reference methodologies. In general, volatile compounds are lost throughout the different steps of the production process. Highest losses are reported between pulp and juice samples and the main volatile compounds lost were hexanal and E-2-hexenal. Butyl acetate were not affected by the production process. The major constituents of apple juices and aromas are E-2- hexenal, 2-hexen-1-ol and 1-hexanol. A large variability was observed between batches which may be a consequence of maturity level and cultivar type. The experiment showed that the production process influences the concentration of the volatile compounds in the apple juice

Date of Award	29 May 2018
Original language	Portuguese
Awarding Institution	Universidade Católica Portuguesa
Supervisor	Helena Čížková (Supervisor), Vojtěch Kružík (Co-Supervisor) & Ana Maria Gomes (Co-Supervisor)