 หัวเรื่อง:ไม่มีชื่อไทย (ชื่ออังกฤษ : Comparative Studies of Limonin and Naringin Distribution in Different Parts of Pummelo [Citrus grandis (L.) Osbeck] Cultivars Grown in Thailand) ผู้เขียน: Suwanna Pichaiyongvongdee, Ratiporn Haruenkit สื่อสิ่งพิมพ์:pdf AbstractSeven pummelo cultivars: Kao Numpueng (KNP), Thong Dee (TD), Kao Paen (KP), Kao Yai (KY), Tha Knoi (TK), Kao Tanggwa (KTG) and Pattavee (PV) grown under Thai pummelo fruit conditions were selected for comparative studies on the distribution of limonin and naringin in various parts of the fruit. In this study, the highest amount of limonin was detected in the seeds of all cultivars. Lesser amounts were detected in albedo followed by flavedo, segment membranes and juice. The limonin content in the seeds ranged from 1375.31- 2615.30 ppm, with the lowest amount in the juice being 10.07–29.62 ppm. The limonin in albedo in decreasing order of cultivars was: TK, TD, KTG, KNP, PV, KY and KP (352.72-133.58-ppm). The limonin in flavedo in decreasing order of cultivars was: PV, TD, KP, KNP, TK, KTG and KY (295.49-130.16 ppm), while in segment membranes the decreasing order of cultivars was: PV, KTG, KNP, TD, KY, KP and TK (293.14–85.81 ppm). Naringin was found in a greater amount than limonin in all fruit parts of the cultivars studied. The order of fruit parts that contained naringin in a decreasing amount was: albedo, flavedo, segment membranes, seeds and juice. The order of cultivars containing naringin in the albedo in a decreasing amount was: KTG, KNP, KP, KY, TK, PV, TD (28,508.01–10,065.06 ppm). In the flavedo in decreasing amounts, the cultivar order was: PV, KTG, KNP, KP, KY,TD and TK (8,964.24–2,483.96 ppm), while in the segment membranes the decreasing order was: KTG, KY, TD, TK, PV, KP and KNP (4,369.50–1,799.48 ppm). In the seeds, the decreasing order was: PV, KTG, KNP, TD,and KP (426.66- 257.87 ppm). In the juice, the decreasing order was: PV, TK, KY, TD, KNP, KP and KTG (386.45–242.63 ppm). The chemical composition of the pummelo juice samples showed a high content of ascorbic acid in the range of 37.03–57.59 mg/100ml. The total soluble solids range was 7.14–9.45 OBrix, the titratable acidity range was 0.38–0.98(g/100ml) as citric acid, and the pH range was 3.69–4.05. |
หัวเรื่อง:ไม่มีชื่อไทย (ชื่ออังกฤษ : Isolation, Preliminary Enzyme Characterization and Optimization of Culture Parameters for Production of Naringinase Isolated from Aspergillus niger BCC 25166) ผู้เขียน:กนกพรรณ ธรรมวัตร, Pongsuda Pongtanya, Vitchuporn Juntharasri,  ดร.ภัชราพร วงศ์วิฑูรยาพร, อาจารย์ สื่อสิ่งพิมพ์:pdf AbstractFrom isolation of fungi capable of hydrolyzing naringin by growing the fungi at 28?C on
selective synthetic minimal medium, pH 5.8, containing 0.1% naringin, 348 fungi were isolated from
128 various host samples, collected from 11 different sources in Thailand and China. Primary screening
of all 348 fungi was done by cultivation of the fungi at 40?C for 7 days in synthetic minimal medium,
pH 4.0, added with 0.1% naringin, and by investigation of the naringin hydrolysis of the fungal culture
filtrate at pH 4.0, 40?C, for 23-48 hours. Forty fungal isolates were obtained. Secondary screening was
performed by measurement of both glycosidase activities, ?-L-rhamnosidase and ?-D-glucosidase at
40?C, pH 4.0, and naringinase activity at the temperatures of 50, 55 and 60?C and at both pH 3.0 and 4.0
of the culture filtrates from all 40 fungal isolates. Aspergillus niger BCC 25166 was selected and
genetically identified. The optimum pH and temperature of the enzyme in crude extract were investigated.
The result showed that all naringinase, ?-L-rhamnosidase and ?-D-glucosidase activities had identical
optimum pH of 4.0. However, the optimum temperature of naringinase and ?-L-rhamnosidase was 60?
C, whereas that of ?-D-glucosidase activity was in the range of 60? to 70?C. Optimization of the medium
and conditions for enzymes production in submerged fermentation found that the suitable inoculum
concentration and medium were 105 spores/ml and Czapek-Dox medium, pH 4.0, containing 0.1%
naringin, respectively. The maximum naringinase production of this fungus (117.77 U/mg protein)
could be obtained by supplement of the medium with 3.75 g/l rhamnose as another carbon source and
using 2.5 g/l NaNO3 as its nitrogen source. For high production of ?-L-rhamnosidase (303.20 U/mg
protein), 2.5 g/l soya peptone should be used instead. |
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หัวเรื่อง:ไม่มีชื่อไทย (ชื่ออังกฤษ : Effect of Chemical Treatments to Reduce the Bitterness and Drying on Chemical Physical and Functional Properties of Dietary Fiber Pomelo Powder from Citrus grandis (L.) Osbe ผู้เขียน:Suwanna Pichaiyongvongdee, Boonyakrit Rattanapun สื่อสิ่งพิมพ์:pdf AbstractThe pomelo albedo was selected from three cultivars—Kao Nampung (KNP), Thongdee (TD) and Kao Yai (KY). KNP was a suitable cultivar for preparing dietary fiber powder because it had high crude fiber content and the limonin and naringin contents were lower than for TD and KY. Limonin and naringin are the main bitter components of pomelo albedo which need to be reduced. Three chemicals were used to reduce the bitterness of the pomelo albedo—NaCl (1%, 3%, 5%), CaCO3 (1%, 3%, 5%) as well as various pH levels using 0.1 N NaOH solution (pH 7, 8 and 9). The results showed that all chemicals treatment could reduce the limonin and naringin contents (P ? 0.05) but adjusting the organoleptic quality to pH 7 had the highest odor score and the lowest score for bitterness. Two drying methods were studied: freeze drying was conducted at -40 ?C for 14 hr and the three conditions for tray drying were 50 ?C for 5.5 hr, 60 ?C for 4.5 hr and 70 ?C for 2 hr. The freeze dried pomelo albedo powder had better physical, chemical and functional properties than the samples that were tray dried (P ? 0.05). The water holding capacity and swelling capacity of the dietary fiber pomelo albedo powder were compared with commercial cellulose (carboxymethyl cellulose). It was found that the pomelo albedo dietary fiber powder had better functional properties than the commercial cellulose based on scanning electron microscopy. Thus, dietary fiber pomelo albedo powder can be used as a functional ingredient or in industrial applications using food products. |