The use of instant controlled pressure drop (DIC) method improves the extraction of bioactive compounds from 'Hass' avocado seed

Avocado seed represents 12-16% of the fruit and is considered as an underutilized resource that makes it a matter of concern regarding its final disposal by the avocado processing industry. The extraction of bioactive compounds from agro industrial wastes is an alternative to take advantage of in order to generate products of commercial and/or social interest with high economic value. The instant controlled pressure drop (DIC; détente instantannée contrôlée) is a technology that promises to improve the extraction of bioactive compounds by a thermo-mechanical pretreatment of the HTST type (high temperature short time) combined with an instantaneous vacuum decompression. The aim of this work was to evaluate the use of DIC technology as a treatment of 'Hass' avocado seeds to improve the extraction of phenolic and flavonoid compounds, as well as to evaluate the antioxidant capacity of the extracts. Two treatment conditions were used, the first (PT1) consisted of submit the seeds to a pressure of 5 bar during 30 s at 49°C, while the second (PT2) consisted of 6 bar, by 40 s at 74°C compared with untreated samples. Methanolic extracts were used to quantify the total phenolic compounds (TPC) and total flavonoids (TF) by spectrophotometric methods. Total antioxidant capacity was determined by the DPPH and ABTS methods. There was no statistical significant difference in the TPC contents of extracts obtained from PT1 and PT2; however, both treatments increased up to 5 times the phenolic extracted compared to extracts of non-treated seeds. The PT2 extracts showed a higher content of total flavonoids. PT1 and PT2 allowed increasing three times the antioxidant capacity of seed extracts. However, the increases of phenolic and flavonoids did not correlate directly with increases in antioxidant capacity.