Optimization of calcium pectinate gel production from high methoxyl pectin.

BACKGROUND: Calcium pectinate (CaP) gel is traditionally prepared by de-esterifying high methoxyl pectin (HMP) to low methoxyl pectin (LMP), followed by gelation with calcium. To save both time and cost in the production of CaP gel, an alternative method was developed by the addition of CaCl2 to HMP at alkaline pH. To optimize the production, response surface methodology (RSM) was used to investigate the effects of temperature (30-50 °C), time (20-40 min) and pH (8-10) on yield, calcium content of the CaP gel and the degree of esterification (DE) of pectin following decalcification of CaP (DC-pectin). RESULTS: The linear term for pH had a significant effect (P < 0.01) on all three responses, whereas interaction effects were not significant (P > 0.01), except on the calcium content (P < 0.01). The optimized process conditions (temperature, time and pH) to obtain maximum CaP-HMP gel yield (88.83%) were 50 °C, 40 min and pH 9.6, and for the highest calcium content (97.23 mg g-1 ) they were 40 °C, 30 min and pH 9.7. DC-pectin was a typical LMP with DE varying from 26.92% to 50.33%. The DE of DC-pectin could be predicted by a model that proved significant (R2  = 0.9888). CONCLUSION: The optimum conditions were established to produce CaP gels from HMP with high yield and calcium content. Also, LMP with predictable DE can be produced following a significant model. This study provides new insights into the production and application of CaP gel. © 2021 Society of Chemical Industry.

Cyanogenesis in Macadamia and Direct Analysis of Hydrogen Cyanide in Macadamia Flowers, Leaves, Husks, and Nuts Using Selected Ion Flow Tube-Mass Spectrometry.

Macadamia has increasing commercial importance in the food, cosmetics, and pharmaceutical industries. However, the toxic compound hydrogen cyanide (HCN) released from the hydrolysis of cyanogenic compounds in Macadamia causes a safety risk. In this study, optimum conditions for the maximum release of HCN from Macadamia were evaluated. Direct headspace analysis of HCN above Macadamia plant parts (flower, leaves, nuts, and husks) was carried out using selected ion flow tube-mass spectrometry (SIFT-MS). The cyanogenic glycoside dhurrin and total cyanide in the extracts were analyzed using HPLC-MS and UV-vis spectrophotometer, respectively. HCN released in the headspace was at a maximum when Macadamia samples were treated with pH 7 buffer solution and heated at 50 °C for 60 min. Correspondingly, treatment of Macadamia samples under these conditions resulted in 93%-100% removal of dhurrin and 81%-91% removal of total cyanide in the sample extracts. Hydrolysis of cyanogenic glucosides followed a first-order reaction with respect to HCN production where cyanogenesis is principally induced by pH changes initiating enzymatic hydrolysis rather than thermally induced reactions. The effective processing of different Macadamia plant parts is important and beneficial for the safe production and utilization of Macadamia-based products.

Alliin alters gut microbiota and gene expression of colonic epithelial tissues.

Alliin is a natural organosulfur-containing phytochemical in garlic. It is possible that alliin can regulate the gut microbiota for its strong antimicrobial activity against many pathogens. Here, we assessed whether alliin impacts the distal small intestinal bacteria, hence the cecal microbiota, thus altering the gene expression of colonic epithelial tissues (CETs). Eighty mg/kg alliin was orally administered to rats for 14 days, and the 16S rDNA from small intestinal and cecal microbiota as well as mRNA from CETs were sequenced and analyzed. The results showed that alliin consumption affected microbiota composition in both the small intestine and cecum, although there was only one specific genus, Allobaculum that was significantly altered in the rat cecum. The altered composition of microbiota indirectly impacted 174 genes in the CETs. Specifically, five genes, including RT1-Ba, RT1-Bb, Cd80, Madcam1, and Aicda, indicated this consumption related to the intestinal immune network for IgA production. PRACTICAL APPLICATIONS: We firstly reported alliin consumption in vivo potentially affected the intestinal immunity of healthy rats by slightly alteration of microbiota composition in small intestine and cecum. The alteration subsequently amplified, resulting in the change of the colonic epithelial expression of several genes related to the intestinal immune network for IgA production. Hence, we suggested the alliin consumption may potentially affect the immune system of healthy individuals by alteration of gut microbiota and epithelial gene expression.

Characterization of phenolic constituents inhibiting the formation of sulfur-containing volatiles produced during garlic processing.

Garlic (Allium sativum L.), which is a widely distributed plant, is globally used as both spice and food. This study identified five novel phenolic compounds, namely, 8-(3-methyl-(E)-1-butenyl)diosmetin, 8-(3-methyl-(E)-1-butenyl)chrysin, 6-(3-methyl-(E)-1-butenyl)chrysin, and Alliumones A and B, along with nine known compounds 6-14 from the ethanol extract of garlic. The structures of these five novel phenolic compounds were established via extensive 1D- and 2D-nuclear magnetic resonance spectroscopy experiments. The effects of the phenolic compounds isolated from garlic on the enzymatical or nonenzymatical formation of sulfur-containing compounds produced during garlic processing were examined. Compound 12 significantly reduced the thermal decomposition of alliin, whereas compound 4 exhibited the highest percentage of alliinase inhibition activity (36.6%).

Characteristics of two calcium pectinates prepared from citrus pectin using either calcium chloride or calcium hydroxide.

Calcium pectinate (CaP) was prepared from citrus pectin using either calcium chloride (C-CaP) or calcium hydroxide (HO-CaP) as the source of calcium for the reaction. The production yields and the rates of decalcification for the two calcium pectinates were compared and both found to be lower for C-CaP than for HO-CaP. In an attempt to explain these differences, certain chemical and structural characteristics of the two products, including functional groups (-CH3, C═O, COO-), rheological properties, morphology, and egg-box junction zones, were investigated by Fourier transformation infrared (FTIR) spectroscopy, rheology, scanning electron microscopy (SEM), and X-ray diffraction (XRD). The results from FTIR showed that, with an increase in calcium content, the wavenumber values and peak areas of FTIR for -CH3, C═O, and COO- groups all changed dramatically for C-CaP, while they were virtually unchanged for HO-CaP. Rheological analysis of the CaP gel showed that C-CaP had a stronger cross-linked network structure and a greater range of elastic behavior as compared to HO-CaP. SEM images of two CaP gels showed irregular membranes. C-CaP maintained a tight structure and a smooth surface, whereas HO-CaP was loose and rough. The results from XRD revealed a higher degree of crystallinity within C-CaP than within HO-CaP, which indicated that C-CaP possessed compact, ordered, and stable egg-box junction zones while the junction zones in HO-CaP were metastable and loose.

Structure and protective effect on UVB-induced keratinocyte damage of fructan from white garlic.

The fructose polymer fructan was extracted from white garlic and fractionated using DEAE cellulose 52 and Sephadex G-100 columns to characterize its chemical composition and protective effect against ultraviolet radiation b (UVB) induced human keratinocyte (HaTaC) damage. Gel permeation chromatography, high performance anion exchange chromatography, infrared spectroscopy and 1D and 2D nuclear magnetic resonance spectroscopy were used to determine the chemical composition and functional characteristics of the garlic fructan (GF). GF was a homogeneous polysaccharide with a molecular weight of 4.54 × 10(3)Da. It was a member of the 1-kestose family, and it was composed of fructose and glucose at a ratio of 14:1. The main chain of GF was composed of (2→1)-ß-D-fructopyranose linked to a terminal (2→1)-α-D-glucopyranose at the non-reducing end and a (2→6)-ß-D-fructopyranose branched chain. The degree of polymerization was 28. Preliminary tests described herein indicated that GF may be effective in protecting HaTaC from UVB-induced damage.

Analysis of anti-platelet aggregation components of Rhizoma Zingiberis using chicken thrombocyte extract and high performance liquid chromatography.

BACKGROUND: The conventional procedure for screening bioactive components from traditional Chinese medicine is time-consuming, expensive and low efficient. Therefore, some alternative strategies are needed urgently. A novel method for screening anti-platelet aggregation components from oleoresins was developed using chicken thrombocyte extract and high performance liquid chromatography. METHODS: The anti-platelet aggregation components of oleoresins were combined with receptors, channels and enzymes of chicken thrombocytes under physiological environment. Unbound substances were washed away and bound compounds were eluted using specific phosphate buffered solution (PBS). Compounds released from target sites were collected and analyzed by high performance liquid chromatography and LC-MS. The activity of three compounds which were screened from this model was confirmed using platelet aggregation pharmacology in vivo. RESULTS: There were four typical compounds that bound to the thrombocytes: 6-gingerol, 8-gingerol, 6-shogaol and 10-gingerol, and all had shown anti-platelet aggregation activities. Eight-gingerol displayed the best anti-platelet aggregation effect. CONCLUSIONS: Chicken thrombocyte extract can be used to isolate chemicals that are ligands of the receptor or other bio-targets on the platelet. This may therefore be a simple and efficient method to screen for anti-platelet aggregation compounds from traditional Chinese medicine.

Simultaneous determination of trilobolide-6-O-isobutyrates A and B in Wedelia trilobata by gas chromatography.

A simple, sensitive, and specific gas chromatographic (GC) method was developed to determine the main bioactive sesquiterpene lactones, trilobolide-6-O-isobutyrates A and B (TBO-A and TBO-B), in Wedelia trilobata, a useful folk herb. A commercially available HP-5 capillary column (30 m x 0.25 mm i.d. x 0.25 microm) was utilized for the direct determination of TBO-A and TBO-B in W. trilobata. Calibration curves were obtained by spiking authentic compounds and the internal standard (ferulic acid) into W. trilobata samples before extraction. Extraction was carried out by refluxing the dried herb (0.5 g) for 1 h in methanol (25 mL). All calibration curves showed good linear regressions (r2 > 0.992) within test ranges. The assay was reproducible and accurate with the overall intraday and interday relative standard deviations and accuracies of less than 10% and more than 90%, respectively. The developed GC method was successfully utilized to analyze the TBO-A and TBO-B in aerial parts and flowers of W. trilobata, indicating that it was suitable for the quality control of this commonly used herb and related traditional Chinese medicines.