Polysaccharides Identification And Processing Properties Variation Of Almond Gum

Almond gum, a transparent substance that is secreted by almond trees of Rosaceae in adverse circumstances, belongs to one kind of original peach gum in food gum. Traditional Chinese medicine believes that original peach gum are bitter, benefit vital energy, invigorate the circulation of blood, and quench thirst. In recent years, peach gum have proved to be effective for treatment for the stone in urinary system, leukaemia adjuvant therapy, and Diabetes therapy. Along with cultivation area of almond increasing recently in China, almond gum will hold larger and larger proportion in original peach gum. Therefore, it is important for investigating constituents and processing characteristics of almond gum.Based on data collection and generalization, the author carried temperatrue treatment, concentration treatment, acid and alkali environment treatment, and different additive treatment mutiple with variables control, and systematically investigated the effect of purification techniques, compositions and structures, temperature, concentration, pH value, and different additive on processing characteristics of almond gum including texture properties rheological properties intrinsic viscosity, crystal properties, hydrolysis, and collaborative properties using Ion Chromatograph, Chromatographic Infrared Analyzer, X-Ray Diffraction Instrument, Brookfield DV-II+viscometer, and TA-XT2i texture analyzer. In addition, variance analysis, regressed curves, and response surface methodology were applied to analyze the data. The main results are as follows:(1) Determination of definition of natural food gum. Natural food gum is one kind of edible viscous polysaccharides seeped from tree trunk, and is also called natural food gum polysaccharide. Besides the essential characteristics of food gum, natural food gum should be derived from tree trunk and composed of polysaccharides without the need for gum extraction.(2) Determination of purification technology of almond gum. The extraction technology of almond gum was improved without destructing the physiological activity of almond gum polysaccharides. The optimum processing conditions of almond gum polysaccharides were determined as mass percentage of 4%, extraction temperature of 80℃, extraction time of 6 h, pH value of 13 under which the extraction percentage of almond gum polysaccharides was 54.89%.(3) Identification of components of almond gum. The content of water, polysaccharide, protein, and ash in almond gum was 5.21%,62.41%,27.62%, and 4.76%, respecively, showing that the main components of almond gum were polysaccharides and proteins. For monosaccharide, the content of GluA, xylose, galactose, arabinose, rhamnose, and fucose was 24.35%,15.36%,33.75%,31.60%, 0.74%, and 0.31%, respectively. For amino acid, the content of Thr, Gly, Ala, His, Arg, Phe, Ser, Glu, Asp, Pro, Val, and Tyr was 37.85%,21.91%,11.04%,8.71%,5.49%, 3.98%,3.31%,2.54%,1.75%,1.74%,0.94%, and 0.75%, respectively.(4) Prediction of structures of almond gum. The main chain of almond gum polysaccharide was possibly composed of 1,6-linked Galp and 1,4-linked Araf. Non-reducing end group was 1-linked Fucp, 1-linked Ribf, or 1-linked GluA. Branching point was mainly located in 1,2,6-linked Galp.(5) Texture properties of almond gum. K-W teset analysis indicated that chi-squared statistic was 2224.405, concomitant probability was less than 0.001, suggesting there were significant differences (P<0.01) between texture properties of almond gum in different ambient conditions. If the chi-squared statistic was 2790.955 and concomitant probability was less than 0.001, there were significant differences (P< 0.01) between texture properties of almond gum with different acid or alkali treatment. Using K-W test of different concentration of NaCl- almond gum, chi-squared statistic was 3574.415, and concomitant probability was less than 0.001. Using K-W test of different concentration of CaCl2- almond gum, chi-squared statistic was 198.356, and concomitant probability was less than 0.001. These suggested that both NaCl and CaCl2 had a markly significant effect on texture properties of almond gum.(6) Rheological properties of almond gum. Soluble almond gum in solution were increased with the increase of almond gum with the mass pecent ranging from 2% to 6%, and the solution were Newton liquid. The shear stress of almond gum was sensitive to temperature and changed violently with the temperature raise. Shaking time had a markely significant effect on dissolution of almond gum. Under certain conditions, the shear stress of the supernatant of almond gum presented increasing trend with "S" shape. The pH value had a markely significant effect on rheological properties of the supernatant of almond gum. The pattern of NaCl affecting rheological properties of the supernatant was the same with that of CaCl2 affecting the rheological properties.(7) The viscosity properties of almond gum. Both of increase and decrease of pH value had significant effect on the viscosity of almond gum with P<0.01. The variation equations of pH7-13 and PH7-1 were y=1.492 81+188.232 49e(-x11.35501), y=0.954 98+0.177 93e(x13.16578), respectively. The mass fractions of almond gum had significant effect on the viscosity of almond gum with P<0.01. The variation equation of the viscosity was y=4.130 61+0.054 73e(x11.54550) with the mass fractions ranging from 0.1%-10.0%. Ambient temperature had significant effect on the viscosity of almond gum with P<0.01. The variation equation of the viscosity was y=0.98813+6.92983e(-x118.04873) with the ambient temperature ranging from 20-90℃.(8) Crystalline properties of almond gum. Crystallization degree of almond gum hydrolysate was measured at different pH values. And effects of different pH values on crystalline attributes of almond gum were studied. Variation of pH values not only enabled almond gum (amorphous substance) to show crystalline attribute, but siginificantly affected the crystalline phases at 1% level. With decrease of pH values, the mathematical model of crystallinity variation of almond gum was y=10.942 01 e-(x-2.23006)2/1.872403 (R2=0.851 75). In contrast, the mathematical model of crystallinity variation of almond gum was y=-8.838 22+1.381 18x (R2=0.89675).(9) The dissolution properties of almond gum. The dissolution proterties and the change of almond gum were studied to clarify the effect of pH value and temperature on the dissolution character of almond gum. Results showed that temperature had significant effect on expansion with P=0.018 (>0.01,<0.05) and F=3.813, but did not had significant effect on dissolubility with P=0.706 (>0.05) and F value being 0.627. The change patterns showed "∨" shape and "∧" shape with the ambient temperature ranging from 60-85℃. The pH value had very significant effect on both of expansion and dissolubility with P<0.01 and F value being 62.312,280.196. The change patterns showed "∨" shape and "(?)" shape.(10) Collaborative properties of almond gum. The viscosity of blend of boracic acid, p-nitrophenol, and almond gum declined at a exponential function with shear rate increase, whereas the shear stress increased at a exponential function with shear rate increase. The viscosity of blend reached a maximum with addition of boracic acid of 0.175% and p-nitrophenol of 0.30%. Texture property curves of almond -xanthan gum blends had significance difference (P<0.01) in general with different accession amounts of almond gum. Significant differences (P<0.05) were found in hardness; Extremely significant differences (P<0.01) were found in bondability; while no significant differences were found in brittleness, flexibility, cohesiveness, adhesivity, chewiness, and recoverability. The hardness of Xanthan gum slightly decreased first, and then fast increased with increase of the amount of almond gum. The Xanthan gum hardness slightly decreased and then suddenly increased with increase of the amount of almond gum. The Xanthan gum bondability constantly decreased with increase of the amount of almond gum. Generally, the collaborative effect of almond gum and Xanthan gum showed diverse change rules.Compared to studies on peach gum, the creative points in this study are below:(1) The components and structures of almond gum were first reported.(2) Almond gum were first found to show rystalline properties under the particular circumstances and have the capacity of converting non-crystal to crystal.(3) The processing properties of almond gum were first investigated.