Stability of Apple Polyphenols as a Function of Temperature and pH

The effect of heat treatment on apple polyphenols was investigated at six different temperatures over three different lengths of time. Apple polyphenols, after heat treatment, maintained similar concentrations in solution compared to the control (at room temperature). The effect of pH on apple polyphenols was investigated at 11 different pH levels and at 2 different temperatures. The pH-optimum for apple polyphenols proved to be 5.0. Two apple polyphenol concentrations, three vitamin C concentrations, two sugar concentrations, and two different temperatures were chosen to investigate the effect of apple polyphenols on vitamin C. Apple polyphenols showed good stability and can be used in many types of food products.     

Characteristics of traditionally processed shea kernels and butter

The traditional production of shea butter requires a heat treatment of the nuts. This study compared the end products derived by two commonly used heat treatments, namely smoking and boiling followed by sun‐drying. Neither treatment influenced the moisture content of the kernels (8–10%), but the boiling treatment resulted in more free fatty acids (FFA) (6%) and a higher fat content (41%) of kernels. A sensory panel preferred shea butter from boiled kernels because of its soft texture and intense smell. This butter also had the highest values for moisture content (2%), unsaponifiable matter (7%), tocopherol compounds (125 mg g^?1), peroxide value (8 meq O₂ kg^?1), iodine value (53 mg I₂ 100 g^?1) and FFA (2%). Minor variations were noticed in the fatty acid profile. Aside from the use of butter from both boiled and smoked kernels in cosmetics, the butter from smoked kernels will be more suitable for food purposes.     

cis/trans-Isomerisation of triolein,trilinolein and trilinolenin induced by heat treatment

To estimate the trans-fatty acid production of edible oils during the frying process, 1.0 g of triolein, trilinolein and trilinolenin, as representative oils, were heated at 180 °C for a defined period. The amounts of trans-fatty acids in heated triacylglycerols were quantitatively determined by gas chromatography after methylation. It was revealed that heating induced cis to trans-isomerisation of unsaturated triacylglycerols, and that trans-fatty acid amounts increased gradually, depending on the heating period. For example, trans-isomer amounts in triolein, trilinolein and trilinolenin (per gram) were 5.8 mg, 3.1 mg and 6.5 mg, respectively, after 8 h incubation at 180 °C. At that time, the contents of polar compounds contained in the heated triolein, trilinolein and trilinolenin were 22%, 27% and 31%, respectively. When triolein was heated under a N₂ stream, neither trans-isomerisation nor polar compounds were detected. The addition of α-tocopherol (1.0%) to triolein significantly prevented not only lipid oxidation but also trans-isomerisation during heating. A commercially available vegetable oil was also heated under the same conditions as these model oils. Compared with the trans-isomerisation in model oils, the degree of trans-isomerisation in the edible oil was relatively low. Tocopherols in the oil would prevent not only lipid oxidation but also isomerisation. These results suggest that the geometric isomerisation of unsaturated fatty acids during heating accompanies lipid oxidation.     

Effect of heat treatment on foaming properties of ostrich (Struthio camelus) egg white proteins

The effect of heat-treatment on foaming properties of ostrich albumen was investigated. At pH 7.5, coagulation of ovotransferrin (OT) resulted in minimum foaming capacity (FC) and maximum foam density (FD). While both exposure of sulfhydryl groups of ovalbumin (OV) and OT-OV interactions improved FC at lower pH, neither of them had beneficial effect on FC at pH 9. At pH 9, FC and FD were mildly affected by heat-treatment because of less aggregation of OT, then FC decreased due to covalent aggregates composed of ovomucin and OV, but at higher temperatures, higher level of OV unfolding resulted in enhanced FC.     

不同热处理方式对青枣贮藏保鲜效果的影响研究

以西昌地区的青枣为试材,研究不同热处理方式对青枣贮藏保鲜效果的影响.结果表明：适宜条件的热水处理效果较好,其最佳条件为55℃处理10 min,30 d腐烂指数为8.61%,好果率为81.67%,可溶性固形物和酸含量分别为9.4%和4.06%,Vc含量为28.17 mg/100 g.     

S432型浆纱机生产色织品种的上浆实践

为了在S432型浆纱机上顺利地对CJ 11.7/11.7 583/433色织防羽布进行上浆,对浆料配方和上浆工艺进行了优化组合.通过对6种组合方案的浆纱效果进行对比,优选出了合理方案.采用高浓低粘浆料并配以高压浆力,使浆纱增强率提高,好轴率提高,织机效率可达87%,布面质量良好.     

姬松茸多糖对2型糖尿病大鼠代谢及抵抗素基因表达的影响

目的:探讨姬松茸多糖对2型糖尿病(2-diabetesmellitus,2-DM)大鼠糖脂代谢和抵抗素(resistin)基因表达的影响。方法:将Wistar大鼠随机分为5组,A:正常对照组;B:模型组;C:8%姬松茸多糖组;D:4%姬松茸多糖组;E:2%姬松茸多糖组。8周后,测定空腹血糖(FPG)、空腹胰岛素(FINS)、血脂和胰岛素抵抗指数(IR);半定量RT-PCR检测resistin基因mRNA的表达水平。结果:姬松茸多糖治疗组FPG、FINS、TG、LDL、VLDL、CH、IR及resistin基因mRNA的表达均低于模型组(P0.05),而HDL的含量则高于模型组。结论:姬松茸多糖可抑制resistin基因表达,降低胰岛素抵抗;降低2-DM大鼠血糖和改善其脂代谢紊乱。     

不同生长调节剂对果蔗产量和品质的影响研究(上)

研究结果表明:植物龙既能使果蔗显著增产,又能使果蔗增加甘蔗糖分,还能降低蔗茎纤维份而使蔗茎更加泡脆,是唯一可在果蔗生产上单独应用的生长调节剂;稀施美能使果蔗极显著增产、蔗茎纤维份降低而变得更泡脆,但却会使果蔗糖分轻微下降,故其要与植物龙配合施用才可在果蔗生产上应用;硕丰481能使果蔗增产极显著,纤维份含量降低,蔗茎泡度增加,但却会使果蔗糖分明显降低,故其也要与植物龙配合施用才可应用于果蔗生产;喜田宝能使果蔗显著增产,蔗茎泡度增加,但却会使果蔗糖分明显降低,也必须与植物龙配合施用才能在果蔗生产上应用;赤霉素能使果蔗明显增产,蔗茎变泡,但却会使果蔗糖分降低,也必须与植物龙配合施用才可在果蔗生产上应用。     

Scrubbing carbon dioxide prevents overestimation of insect mortality in long-duration static phosphine toxicity assays

Exposing insects to toxicants such as phosphine (PH₃) in sealed chambers is a common procedure in fumigant efficacy testing. During long exposures, carbon dioxide (CO₂) produced by metabolic processes of fed insects may accumulate in the vessel. As CO₂ enhances the toxicity of several fumigants, concomitant exposure of fumigant and CO₂ may lead to erroneous measurements of insect mortality and thus fumigant toxicity. In this study, the effect of a CO₂ scrubber such as soda lime (a solid formulation of wet hydroxides of calcium, sodium and potassium) or periodic flushing of the headspace, on insect mortality in static PH₃ toxicity assays was compared with an “unscrubbed” (no intervention) treatment. Soda lime was highly effective in removing CO₂ from the headspace of sealed chambers, without measurable loss of PH₃. Mortality of Sitophilus oryzae (L.) adults treated with phosphine in chambers scrubbed with soda lime or flushed (opened) daily was considerably lower than in unscrubbed chambers. Twenty grams of soda lime per litre of exposure chamber is recommended to obtain accurate static fumigant mortality results.     

Phosphine resistance in stored-product insects collected from various grain storage facilities in Morocco

Despite heavy dependence on phosphine (PH₃) for fumigating stored products, the resistance status of insect pests in Morocco has never undergone a thorough investigation. Some control failures with PH₃ were reported in Morocco, and a previous study showed two field populations of Sitophilus oryzae to be highly resistant to phosphine.We surveyed phosphine resistance in field populations of three major insect pests of stored wheat in Morocco. Around 32% of the samples collected at different storage facilities were found to be infested with one or more species of stored-product beetles. First-generation adult beetles, cultured from the field samples, were subjected to a discriminating dose test for phosphine resistance using an FAO method. The results indicated that, with the exception of one population of S. oryzae, all samples tested contained phosphine-resistant individuals. Treatments at up to 1.8 g m⁻³ of phosphine for 20 h, or at 0.18 g m⁻³ for up to 5 days, indicated that a high degree of resistance was already selected in some of the insect populations.Tests using [³²P]-radiolabelled phosphine showed that the mechanism of resistance in the three insect species tested involved a reduced uptake of the fumigant. The study has highlighted an urgent need for reviewing current fumigation practices in Morocco to ensure effective use of phosphine and avoid further selection of resistance.