ABSTRACT
Starch residue samples from two Australian sweet potato varieties (Beauregard and Northern Star) and two Indonesian sweet potato varieties (Bis192 and Bis183), and a commercial sample of sweet potato starch residue, were studied for their pectins. Pectins were extracted using 0.1M HCl, 0.05M NaOH, 0.1M HCl/0.75% SHMP and 0.05M NaOH/0.75% SHMP. Hydrolysis of residual starch in the cell wall of sweet potato using heat stable -amylase and amyloglucosidase was employed prior to pectin extraction to eliminate starch contamination. Pectins were characterised for yield, galacturonic acid content (GA), and the degree of esterification (DE). Conventionally, pectin is characterized by titration, photometry and HPLC. However these methods are cumbersome and time consuming. On the other hand, 13C CP/MAS solid-state NMR, a non-destructive, efficient and direct method, has been found to be well-suited for these purposes since pectin has well-defined 13C NMR spectra. Therefore 13C CP/MAS solid state NMR was used for pectin determination. The pectin characteristics are dependent on variety and extraction process; however, the extraction methods gave variable results. Yields were between 7 and 30% of the cell wall. GA varied from 27 to 80% with the highest found in Bis192 extracted using NaOH/SHMP. DE varied between traceable and 57%. HCl extraction gave higher DE, while NaOH/SHMP caused demethylation. Overall, this study demonstrated that pectin from sweet potato starch residue is mainly low in methoxyl groups.
ABSTRACT
Starch residue samples from two Australian sweet potato varieties (Beauregard and Northern Star) and two Indonesian sweet potato varieties (Bis192 and Bis183), and a commercial sample of sweet potato starch residue, were studied for their pectins. Pectins were extracted using 0.1M HCl, 0.05M NaOH, 0.1M HCl/0.75% SHMP and 0.05M NaOH/0.75% SHMP. Hydrolysis of residual starch in the cell wall of sweet potato using heat stable -amylase and amyloglucosidase was employed prior to pectin extraction to eliminate starch contamination. Pectins were characterised for yield, galacturonic acid content (GA), and the degree of esterification (DE). Conventionally, pectin is characterized by titration, photometry and HPLC. However these methods are cumbersome and time consuming. On the other hand, 13C CP/MAS solid-state NMR, a non-destructive, efficient and direct method, has been found to be well-suited for these purposes since pectin has well-defined 13C NMR spectra. Therefore 13C CP/MAS solid state NMR was used for pectin determination. The pectin characteristics are dependent on variety and extraction process; however, the extraction methods gave variable results. Yields were between 7 and 30% of the cell wall. GA varied from 27 to 80% with the highest found in Bis192 extracted using NaOH/SHMP. DE varied between traceable and 57%. HCl extraction gave higher DE, while NaOH/SHMP caused demethylation. Overall, this study demonstrated that pectin from sweet potato starch residue is mainly low in methoxyl groups.
ABSTRACT
Aim A combination of PPI and 1000 mg amoxicillin/500 mg clarithromycin twice daily for 2 weeks has been proven effective in the eradication of H. pylori. Most studies suggested that treatment for 7 and 10 days may be equally effective. Few data are available on the effi cacy of 5-day triple therapy. Aim of this study was to compare 5-day and 7-day rabeprazole triple therapy for eradication of H. pylori infection. Methods We prospectively studied 60 consecutive H. pylori-infected patients who came to hospitals in six centres in Indonesia and who underwent upper endoscopy and biopsy. H. pylori infection was confi rmed if two rapid urease tests (Pronto Dry) and histology or urea breath test were positive. Patients were assigned to either an open-labelled 5-day or 7-day course of oral amoxicillin 1000 mg b.i.d., clarithromycin 500 mg b.i.d., and rabeprazole 10 mg b.i.d. (RAC). Four weeks after therapy, all patients had a repeated UBT for evaluation of the presence of H. pylori. Results Of the 60 patients (42 males and 18 females) with mean age (± SD) 47.63 ± 13.93 years, range 21–74 years, 25 patients (41.7%) had 5-day treatment and 35 patients (58.3%) had 7-day treatment. With 5-day treatment, 18 patients (72%) and with 7-day treatment 32 patients (91.4%) became negative for H. pylori infection. The eradication failure was found on 7 patients (28.0%) in 5-day treatment and 3 patients (8.6%) in 7-day treatment. Conclusions The study showed that the eradication of H. pylori infection by triple rabeprazole-based treatment in 7-day is still better than in 5-day.