浅析糖梨的种植栽培技术

糖梨的种植技术与园地、栽植、施肥、修剪、病虫害等各个因素都息息相关,其具有非常强的技术性。通过简要阐述糖梨的园地选择,具体讲解糖梨栽培管理技术,介绍病虫害防治的具体实施措施等相关技术,借以提高糖梨种植技术的水平,从而实现糖梨的优质高产,为农民获得更大的经济效益。

Sorbitol-based osmotic diarrhea:Possible causes and mechanism of prevention investigated in rats

AIM: To study the possible causes of sorbitol (S)-based diarrhea and its mechanism of reduction by rice gruel (RG) in cecectomized rats. METHODS: S was dissolved either in distilled water or in RG (50 g/L) and ingested as a single oral dose (1.2 g/kg body mass, containing 0.5 g/L phenol red as a re-covery marker) by S (control) and S + RG groups (n = 7), respectively. This dose is over the laxative dose for hu-mans. Animals were sacrificed exactly 1 h after dose in-gestion, without any access to drinking water. The whole gastro-intestinal tract was divided into seven segments and sampled to analyze the S and marker remaining in its contents.RESULTS: Gastric-emptying and intestinal transit were comparatively slower in the S + RG group. Also, the S absorption index in the 3rd and last quarter of the small intestine (24.85 ± 18.88% vs 0.0 ± 0.0% and 39.09 ± 32.75% vs 0.0 ± 0.0%, respectively, P < 0.05) was sig-nificantly higher in the S + RG group than in the control group. The S absorption index and the intestinal fluid volume are inversely related to each other. CONCLUSION: The intestinal mal-absorption of S is the main reason for S-based osmotic diarrhea. Where RG en-hanced the absorption of S through passive diffusion, the degree of diarrhea was reduced in cecectomized rats.

Carbohydrate malabsorption in patients with non-specific abdominal complaints

Non-specific abdominal complaints are a considerable problem worldwide. Many patients are affected and many differential diagnoses have to be considered. Among these, carbohydrate malabsorption seems to play an important role. However, so far, only incomplete absorption of lactose is broadly accepted, while the malabsorption of fructose and sorbitol is still underestimated, although in many parts of the world it is much more frequent. Despite the success of dietary interventions in many patients, there are still a lot of unanswered questions that make further investigations

Fructose-sorbitol ingestion provokes gastrointestinal symptoms in patients with eating disorders

AIM:To evaluate gastrointestinal(GI) symptoms and breath hydrogen responses to oral fructose-sorbitol(F-S) and glucose challenges in eating disorder(ED) patients.METHODS:GI symptoms and hydrogen breath concentration were monitored in 26 female ED inpatients for 3 h,following ingestion of 50 g glucose on one day,and 25 g fructose/5 g sorbitol on the next day,after an overnight fast on each occasion.Responses to F-S were compared to those of 20 asymptomatic healthy females.RESULTS:F-S provoked GI symptoms in 15 ED patients and one healthy control(P < 0.05 ED vs control) .Only one ED patient displayed symptom provocation to glucose(P < 0.01 vs F-S response) .A greater symptom response was observed in ED patients with a body mass index(BMI) ≤ 17.5 kg/m 2 compared to those with a BMI > 17.5 kg/m 2(P < 0.01) .There were no differences in psychological scores,prevalence of functional GI disorders or breath hydrogen responses between patients with and without an F-S response.CONCLUSION:F-S,but not glucose,provokes GI symptoms in ED patients,predominantly those with low BMI.These findings are important in the dietary management of ED patients.

THE DETERMINATION OF ADSORPTION ISOTHERMS AND SOLID DEFFUSION COEFFICIENTS OF MANNITOL AND SORBITOL BY LIQUIDCHROMATOGRAPHY TECHNIQUE

The Parameter identification model is proposed for determining the linear adsorptionisotherms and the solid diffusion coefficients by using adsorption chromatography. Axialdispersion coefficients is firstly determined by pulse-respond experiment technique with aninert substance as tracer then the elution curves of chromatography separating the isomermannitol and sorbitol are determined by the chromatographic measuring technique, andfinally the adsorption isotherms and the solid diffusion coefficients of mannitol andsorbitol on Ca2+ resins are estimated by using this model. The results show that the axialdispersion coefficients increase with fluid velocity increasing, the adsorption equilibriumconstants decrease with temperature rising;and the solid diffusion coefficients increasewith temperature rising. The theoretical elution curves are good agreement with theexperimental elution curves of the liquid adsorption chromatography separating themannitol and the sorbitol. The model provides a simple and reliable procedure to estimatethe kinetic and thermodynamic parameters of the adsorption.

Synthesis and Gel Properties of Sorbitol Derivative Gelators

1,3:2,4-di-p-methylbenzylidene-D-sorbitol(MDBS)is known to be an efficient sorbitol derivative gelator.Two new sorbitol derivative gelators were designed and synthesized in contrast to MDBS in order to study the gel properties of gelators with different structures.Their gelation behavior to 30 solvents was investigated.It was found that the gelation behavior was related to the molecular structure of gelators.Compared with MDBS,the gelator with more hydroxyl in the molecular structure could gel water and that with more aromatic ring could gel aromatic solvent.The fibrous and three-dimensional network of the gels was obtained by scanning electron microscopy(SEM).Ultraviolet-visible(UV-Vis)spectroscopy revealed thatπ-πinteraction was one of the main driving forces for the formation of gels.Theπ-πstacking of gelation increases with the number of aromatic rings in the molecular structure of gelator.Fourier transform infrared(FT-IR)spectroscopy revealed that the hydrogen bonding was also the main driving force for the formation of gels.The layered structure of the gels was studied by X-ray diffraction(XRD).

Development of Chitosan Film Incorporating Garlic Oil or Potassium Sorbate as an Antifungal Agent for Garlic Bread

Chitosan is a biopolymer material. Mechanical, physical and barrier properties of different chitosan films incorporating garlic oil at 25, 50 and 100 μL/g chitosan or potassium sorbate at 25, 50 and 100 mg/g chitosan as antifungal agents were studied. Addition of garlic oil or potassium sorbate into the films did not alter their color except at the highest concentration of garlic oil which resulted in a more yellowish film. Garlic oil reduced film strength and elongation but it had no effect on water vapor transmission rate. Potassium sorbate reduced film strength and water vapor transmission rate, but it increased oxygen transmission rate. Films containing garlic oil or potassium sorbate was used to wrap around garlic bread to evaluate its shelf life. The development of mold on the bread surface was observed daily. The results showed that garlic bread wrapped in chitosan film incorporating garlic oil had 23 days shelf life, compared with only 7 days shelf life of garlic bread without wrapping. Garlic bread wrapped by film containing potassium sorbate had 13 days shelf life. Garlic breads wrapped by the films incorporating either garlic oil or potassium sorbate were acceptable in terms of sensory evaluation.

Densities and Viscosities of the Quaternary System Mannitol-Sorbitol- D-Glucose-H2O and Its Ternary Subsystems at 298.15K

To check the applicabilities of the simple density equation and viscosity equation in the semi-ideal solution theory to nonelectrolyte solutions, the densities and viscosities were measured for the quaternary system mannitol-sorbitol-D-glucose-HzO and its ternary subsystems mannitol-D-glucose-H2O and sorbitol-D-glucose-H2O at 298.15K. The results were used to test the applicability of the simple equations for the density and viscosity of the multicomponent nonelectrolyte solution. The agreements between the predicted and measured results are good.

Effective conversion of cellobiose and glucose to sorbitol using non-noble bimetallic NiCo/HZSM-5 catalyst

The tandem hydrolysis and hydrogenation of saccharides into sorbitol is an especially attractive reaction in the conversion of biomass. Here, an economical and efficient bimetallic catalyst for the transformation of glucose and cellobiose into sorbitol is reported. Non-precious metal based catalysts such as NiCo, Ni, and Co, were prepared via modified impregnation method, and NiCo/HZSM-5 showed superior performance for the synthesis of sorbitol(86.9% from cellobiose, 98.6% from D-glucose).Various characterizations, such as Brunner-Emmet-Teler(BET), X-ray diffraction(XRD), transmission electron microscopy(TEM) and X-ray photoelectron spectroscopy(XPS), confirmed that NiCo alloy formed and highly dispersed in NiCo/HZSM-5 catalyst. The high performance of fabricated catalyst would be attributed to the formation of nickel-cobalt alloy over HZSM-5 zeolite surface. High temperature and H_2 pressure were favorable for the tandem hydrolysis and hydrogenation reaction. Besides,the reaction pathway was also proposed based on the kinetics study. Cellobitol was detected as the intermediate in the reaction mixture. Furthermore, in the catalytic stability study, it was found that active metal species of NiCo/HZSM-5 were stable. The deactivation of catalyst would be due to the covering of acidic sites over NiCo/HZSM-5.