Recent research suggesting the existence of potential source of pectin from roselle calyces. Pectin was successfully extracted from seven different varieties of roselle calyces. Pectin extraction was conducted using hydrochloric acid (HCl, 0.03 N, pH 1.5) or ammonium oxalate (0.25% w/v, pH 4.6) at 85⁰C for 1 h. Chemical characteristics of the HCl- and ammonium oxalate extracted pectin were compared. Results indicated that ammonium oxalate exhibited greater efficiency in pectin extraction than HCl. Highest pectin yield at 18.7% was obtained by ammonium oxalate extraction of roselle calyx variety Acc.6 compared to only 9.77% by HCl extraction. The lowest pectin yield at 11.3% and 5.78% were observed respectively in ammonium oxalate and HCl extractions of roselle calyx variety UKMR-3. Some important characteristics of ammonium oxalate extracted pectin of roselle Acc.6 were 5.98% moisture, 3.81% ash, 4.64% methoxyl content, 42.24% anhydrouronic acid (AUA) and degree of esterification (DE) 60%. This study suggested that the high DE% roselle pectin is an alternative source of pectin for food industry.
Angiotensin I-converting enzyme (ACE) plays an important role in reducing blood pressure and
gives an anti-hypertensive effect. Inhibition of ACE mainly results in an overall antihypertensive
effect. The objectives of this study were to determine the ACE inhibition activity in edible bird
nest hydrolysates and the effect of different hydrolysis time of 30, 60, 90, 120, 180 and 240
minutes. Edible bird nest protein was hydrolysed by enzymatic hydrolysis with alcalase and
papain to obtain ACE inhibitory peptides. The results suggested that 60 minutes of hydrolysis
time using alcalase contributed to the best ACE inhibitory activity (IC50 = 0.02mg protein/ml)
which shows edible bird nest protein hydrolysate to be a potent ACE inhibitor that may be used
to decrease blood pressure.