Effects of different processing conditions on the quality of bitter almonds

• Main Authors: Chang, Chia-Wei, 張家瑋
• Other Authors: Lin, Jen-Shinn
• Format: Others
• Language: zh-TW
• Published: 2008
• Online Access: http://ndltd.ncl.edu.tw/handle/60522908265865953515

碩士 === 國立屏東科技大學 === 食品科學系所 === 96 === The analysis methods of amygdalin and benzaldehyde had been established by HPLC. Amygdalin, benzaldehyde and the internal standard were well and efficiently separated, and results of validation tests showed perfect recovery rate and accuracy. The amygdalin contents in bitter almonds showed increasing trend with an increase of storage temperature and a decrease of particle size. The amygdalin contents in bitter almonds were decreased by general processing practices (boiling, roasting, microwaving). The decreases of amygdalin content would be affected by different processing temperature (power) and time. In particular, the lowest amygdalin content was 5.59 mg/g processed by boiling at 80℃ for 60 min; the highest amygdalin content was 23.55 mg/g processed by microwaving at 60% full power (530 W) for 6 min. The contents of benzaldehyde generated by the hydrolysis of amygdalin were found increased in all conditions of practices except those boiling at 100℃. Similarly, the highest benzaldehyde content was 0.66 mg/g processed by microwaving at 60% full power for 6 min. Results of the study had also shown that amygdalin contents were affected by the participation of water during processing, whereas benzaldehyde contents were affected by drying methods. Furthermore, the amygdalin contents of boiled, roasted and microwaved bitter almonds were decreased significantly, when they were grinded after soaked in water. The benzaldehyde contents were lost for 0.1 and 0.02 mg/g, when bitter almonds were roasted at 100℃ for 40 min and microwaved at 60% full power for 6 min, respectively. It was worth to notice that the benzaldehyde contents increased from 0.11 to 0.17 mg/g under boiling at 100℃ for 20 min. Results of the oil analysis had shown that the peroxide value in the oil of bitter almonds were increased with the increasing time of processing at 100℃, and the acidic value of the oil of bitter almonds was increased with production of free fatty acid which was caused by the lipase induced hydrolysis of almond oil. Colors of bitter almonds were darkened with the increasing time of processing. The bitter almonds, processed by boiling at 100℃ for 40 min, have the highest overall acceptability.