山梨糖醇液中含微量甘露醇的成因

目前生产食品添加剂山梨糖醇液的主导工艺由葡萄糖直接加氢还原获得，市售的成品山梨糖醇液中或多或少含有微量的甘露醇。本文阐述了成品山梨糖醇波中含有微量甘露醇的成因。     

Suppression of thermal denaturation of myosin and salt-induced denaturation of actin by sodium citrate in carp (Cyprinus carpio)

The effect of sodium citrate (Na-citrate) on myosin and actin denaturation in myofibrils was investigated. Na-citrate significantly suppressed the thermal inactivation of Ca²⁺-ATPase of carp myosin in a concentration-dependent manner. The effect was greater than that of sorbitol. A similar effect was observed with myofibrils in which myosin is stabilized by F-actin binding. Na-citrate dissolved myofibrils at lower concentration than NaCl. Nevertheless, Na-citrate at 1 M failed to denature F-actin in myofibrils, while 1 M NaCl denatured F-actin almost completely. Na-citrate suppressed the NaCl-induced F-actin denaturation. Sorbitol did not show such protective effect on F-actin denaturation. Moreover, Na-citrate suppressed the freeze denaturation of myofibrils at lower concentration than sorbitol. Thus, Na-citrate was proved to be superior to sorbitol. It was suggested that Na-citrate alone could substitute sorbitol as cryoprotectant in surimi and NaCl as dissolving reagent of myofibril in thermal gel production.     

山梨醇电化学合成技术的改进（Ⅱ）——恒电流电解

研究了阴极材料及工艺条件对葡萄糖电解还原的影响。结果表明,添加剂a（NH4Cl）能有效地降低葡萄糖还原的过电势,抑制析氢,从而使产率大幅度地提高。最佳电解条件为含0．25mol·L(-1)添加剂a的1．0mol·L(-1)葡萄糖溶液,pH为8～9,Zn－Hg阴极,电流密度0．4A·dm(-2),温度32℃。在该条件下通常可得94％的产率。     

Detection of addition of apple juice in purple grape juice

Due to increasing grape juice consumption, quality control is a reality in all countries which produce and consume this product. The most common form of adulteration is by substituting grape juice with apple juice. The adulterated samples can be identified by specific analysis, since apple juice has some compounds that grape has not. There are many studies about the phlorizin and sorbitol content in wines, but in grape juice they are scarce. Therefore, analytical methods to identify the composition of grape juices and determine their authenticity are needed to ensure quality control. The present study aimed to the validation and application of analytical methods for the determination of phlorizin and sorbitol, to detect the addition of apple juice in purple grape juice, by high-performance liquid chromatography. Initially, the methods were validated and tests were conducted by additions of percentages of apple juices in grape juices. Finally, experimental and commercial grape and apple juices were analyzed. Our study found that both methods are effective in detecting the addition of apple juice in grape juice. Four of the 39 commercial grape juices analyzed showed adulteration by the addition of apple juice in grape juice.     

葡萄糖催化加氢制备山梨醇的研究进展

本文报道了目前国内外葡萄糖催化加氢制备山梨醇的研究现状。从所使用的催化剂、生产工艺等方面进行了论述，特别对于非晶态合金催化剂用于葡萄糖加氢制备山梨醇方面的研究作了评述。并对未来的研究方向进行了展望。     

液相色谱法测定山梨醇等几种多元醇的含量

用高效液相色谱法,以Aminex HPX-87H色谱柱为分析柱,0.005mol/L H2SO4为流动相,示差折光检测器,一次进样同时测定样品中的山梨醇、乳酸及几种多元醇(C2～C4)的含量,所得结果良好,相对标准偏差在1%～3%,回收率在95%～105%.     

Preparation and structural analysis of chitosan films with and without sorbitol

The purpose of this study was to clarify the structural changes in chitosan films made with sorbitol. The degree of deacetylation (DD) in the starting chitosan was 85% or 95%. The appearance and cross-sectional characteristics of the films were analyzed by SEM. This showed sorbitol to be a good crosslinking agent, generating the desired miscibility with both types of chitosan. XRD revealed an increase in crystallinity for films without sorbitol and a decrease for films spiked with sorbitol compared with the original chitosan. FT-IR showed that the addition of sorbitol did not change the chemical structure of chitosan and no new types of bonds were created during film formation. Changes in the chemical surrounding of carbon atoms analyzed by CP/MAS ¹³C NMR indicated that the acetic acid solution used partially destroyed the chitosan powder and protonized some groups, enabling sorbitol to be inserted and to form hydrogen bonds in the matrix.     

Impact of sorbitol on the thermostability and heat-induced gelation of bovine serum albumin

The influence of sorbitol (0–40 wt.%) on the thermal denaturation and gelation of bovine serum albumin (BSA, pH 7.0) in aqueous solution has been studied. The effect of sorbitol on heat denaturation of 0.5 wt.% BSA solutions was measured using ultrasensitive differential scanning calorimetry. The unfolding process was irreversible and was characterized by the thermal denaturation temperature (T_m). As the sorbitol concentration increased from 0 to 40 wt.%, T_m increased from 73.0 to 80.9 °C. The rise in T_m was attributed to the increased thermal stability of the globular state of BSA relative to its native state. The dynamic shear rheology of 4 wt.% BSA solutions containing 200 mM NaCl was monitored as they were heated from 30 to 90 °C at 1.5 °C min⁻¹, held at 90 °C for 120 min, and then cooled back to 30 °C at −1.5 °C min⁻¹. Sorbitol increased the protein gelation temperature (ΔT_gel +10 °C for 40 wt.% sorbitol), decreased the isothermal gelation rate at 90 °C, but increased the final shear modulus of the gels cooled to 30 °C. The impact of sorbitol on gel characteristics was attributed to its ability to increase protein thermal stability, increase the attractive force between proteins and decrease the protein–protein collision frequency.     

Some compositional properties of main Malatya apricot (Prunus armeniaca L.) varieties

Malatya apricot (Prunus armeniaca L.) varieties are among the most important agricultural products of Turkey and protected as a geographical indication. In this research, it was aimed to determine some important analytical properties (dry matter, soluble solid content, a_w, ash, titratable acidity, pH, color, total phenolics, total carotenoids, β-carotene, sugars, organic acids, and mineral content) of Malatya apricots and to reveal the characteristic properties that differ these products from the similar ones. The apricot varieties, namely Hac?halilo?lu, Hasanbey, So?anc?, Kabaa??, Çatalo?lu, Çölo?lu, and Hac?k?z that are widely cultivated in Malatya region and other regions (Ere?li, ?zmir, I?d?r, and Bursa) of Turkey were involved in the study. All analytical properties were found to be significantly different (p < 0.05) among different apricot varieties. The results have shown that dry matter and sugar content of Malatya apricot varieties are considerably higher than the other apricot varieties investigated in this study, as well as the data of other researches on apricots. All apricot varieties were found to be a good source of phenolic compounds (4233.70–8180.49 mg of gallic acid equiv/100 g of dry weight), carotenoids (14.83–91.89 mg of β-carotene equiv/100 g of dry weight), and β-carotene (5.74–48.69 mg/100 g of dry weight). Sucrose, glucose, and fructose were determined as the major sugars in all apricot varieties. In addition, sorbitol contents (16.91–26.84 mg/100 g of dry weight) of Malatya apricots were remarkably higher than the other apricot varieties. This was considered to be the one of the unique properties of Malatya apricots. Malic acid was the predominant organic acid in all Malatya apricot varieties. The results have also shown that the potassium content of Malatya apricots was significantly high and these apricots were important sources of Mg, Zn, and Se. This study has revealed that Malatya apricot contains functional food components with high nutritional value.     

Assessment of the ability of five culture media for the detection of Escherichia coli O157

Cattle are a common reservoir for Escherichia coli O157:H7. Prior to confirming its presence in a sample, proper isolation of E. coli O157 is necessary. Consequently, this study evaluated the ability of five commercial plating media to isolate E. coli O157 from 138 samples of fresh cattle faeces, water from water trough and pond, and surfaces of water trough and hay bunk. For the isolation of E. coli O157, samples were enriched in tryptic soya broth, followed by immunoseparation and then plating on SMAC, CT‐SMAC, CHROMagar^? O157, Tellurite CHROMagar^? O157 and Vancomycin Cefixime Cefsoludin CHROMagar^? O157. Real‐time PCR targeting genes stx₁, stx₂ and wzy_O157 was used to confirm selected isolates. When analysed together, CT‐SMAC and CHROMagar^? O157 were the best combination for isolating E. coli O157, giving 79% true‐positive results and only 0.05% false‐negative results.