An Innovative Strategy of Comprehensive Utilization of Tiger Nuts (Cyperus esculentus L.): Simultaneous Extraction of Oil and Glucose Syrup by Amylolysis-assisted Aqueous Extraction Process

Abstract

Abstract The tiger nut (Cyperus esculentus L.) possesses a substantial nutrition yet its industrialization process is characterized by sluggishness. Herein, we introduced a green approach to achieve simultaneous extraction of oil and glucose syrup from tiger nuts via Amylolysis-assisted Aqueous Extraction Process (AAEP). Briefly, tiger nut flour was rinsed to eliminate non-starch polysaccharides and separate the majority of the oil (64.02 %). Followed by liquefaction with α-amylase (AMY), and saccharification with amyloglucosidase (AMG) and pullulanase. Under optimal conditions (AMY dosage: 40 U/g; AMG and pullulanase dosages: 200 U/g and 10 U/g respectively; pH=6.0 during liquefaction at a temperature of 95 oC for 30 min; pH=5.5 during saccharification at a temperature of 55 oC for 150 min; the solid-liquid ratio of 1:5), the AAEP method achieved an oil yield of 89.84 % along with a glucose syrup yield of 89.41 %. Confocal laser scanning microscopy (CLSM) results demonstrated that starch hydrolysis promoted the release of encapsulated oil, which enhanced the extraction efficiency of oil. Overall, our findings highlight that AAEP is an effective industrial approach facilitating comprehensive utilization of tiger nuts.