Health oil preparation from gardenia seeds by aqueous enzymatic extraction combined with puffing pre-treatment and its properties analysis

Gardenia jasminoides Ellis, a typical representative for “homology of medicine and food”, can be used to produce gardenia yellow and edible oil. Here, aqueous enzymatic extraction (AEE) combined with puffing pre-treatment was explored to prepare oil from gardenia seeds. Free oil yield (FOY) by AEE was evaluated in term of selection of enzyme, enzyme combination, as well as puffing ways and conditions. Results suggested that seeds taken as raw materials were better than whole fruit, sequential hydrolysis was superior to single enzymatic hydrolysis. Both wet-heating puffing at 90℃ and dry-heating puffing at 1.0MPa facilitated the release of free oil by AEE, while FOY produced the highest oil yields of 21.8% and 23.2% within 3h, and 58.3%, 68.4% higher than that of un-puffed group, active crocin and geniposide were also completely released. The FOY obtained in this study was far higher than pressing method (10.44%), and close to solvent extraction (25.45%). Also, microstructure analysis indicated that gardenia seeds expanded by dry-heating puffing (1.0MPa) had larger and rougher surface and porous structure than other groups. Moreover, there was no significant difference between oils prepared by various methods in term of nutritional and safety characteristics. AEE coupled with puffing pre-treatment developed is an eco-friendly extraction technology with high efficiency that can be employed to oil preparation enriched with active crocin and geniposide from gardenia seeds.