การพัฒนาสารให้สีธรรมชาติจากดอกอัญชันด้วยเทคนิคโคพิกเมนต์เทชัน

Abstract

The objectives of natural colorant product from butterfly pea flower (BPF) development were to 1) optimize drying process of BPF using microwave vacuum dryer, 2) optimize ultrasonic extraction condition of dried BPF, 3) compare copigmentation in BPF extract using gallic acid and ascorbic acid and 4) evaluate moisture accelerated shelf life of BPF extract powder. BPF was dried at different microwave power (3,600 W and 4,800 W) and different times (15, 20 and 25 min). The optimum condition of drying was microwave power 3,602.05 to 4,537.65 W and drying time 16.80 to 23. 17 min. The significant (pS0.05) parameters on the drying eficiency were yield, moisture, a, total anthocyanin content (TAC), L*, a*and b* as 17.50%, 10.20%, 0.389, 1.09 mg/g dry basic (DW), 43.39, -0.78 and 0.87, respectively. Dried BPF was extracted using ultrasonic extraction (solvent: water and ethanol, extraction temperature: 35ºC and 45ºC, extraction time: 25 and 30 min). The optimum condition of water extraction was 35.10 to 45.00 ºC for 26.67 to 30.00 min. The optimum condition of 50% ethanol extraction was temperature 37.86 to 44.94ºC and extraction time 25.34 to 30.00 min. Those two optimum conditions were found high TAC as 1.51 and 1.50 mgg DW, respectively. BPF extract was copigmented with different copigments (gallic acid and ascorbic acid) at different molar ratio of anthocyanin to copigment (1:10, 1:50 and 1:100) under pH 3, 5 and 7 and heated at 90ºC for 120 min. It was found that the extract using molar ratio of BPF anthocyanin to ascorbic acid at 1:100 had lower color value difference than that of gallic acid and had higher monomeric anthocyanin and longer half - life of anthocyanin than that of gallic acid. Then, the copigmented BPF extract was mixed with 12% maltrodextrin and 8% arabic gum and encapsulated using spray dryer. Chemical analysis showed that yield, moisture, a., TAC, delphinidin content, cyadinin content, L*, a* and b* was 16.10, 6.17,0.404, 1.09 mg/g DW, 0.98 mgg DW, 0.06 mgg DW, 55.45, 4.23 and -22.13 respectively. The moisture accelerated shelf life study of BPF extract powder was performed. It was found that BPF extract powder was packed in aluminium foil pouch with 7-millimeter-thick and kept at 380C with 90% relative humidity was 555 days or I years and 190 days.