Deacidification effects of rice hull-based adsorbents as affected by thermal and acid treatment

Rice hull ash (RHA) was evaluated as a source of adsorbent for edible oil processing, especially its application in reducing free fatty acid (FFA). RHA300, RHA400, RHA500, RHA600, RHA700, RHA800 and RHA900 were prepared by burning rice hulls at 300, 400, 500, 600, 700, 800 and 900 °C, respectively. Increased pyrolysis temperature resulted in an increase in pH (increased alkalinity) of RHAs from 9.53 to 9.98. RHA500 was the most effective in reducing residual FFA, followed by RHA400 and RHA300. About 30-46% reduction of FFA was observed in degummed soybean oil and more than 80% reduction in degummed oil-hexane miscella at 5 g/100 g oil of RHA500. On heating of the ash greater than 500 °C the loss of adsorptive capacity for FFA was shown in case of RHA800 and RHA900. RHA500 reduced about 50% FFA of commercial vegetable oils such as olive oil and corn oil. There was no significant adsorptive difference between the kinds of fatty acids dissolved in isooctane. Acid activation for RHA500acid did not improve the FFA adsorption relative to nonactivated RHA500.     

Comparative study of soybean oil refining using rice hull silicate and commercial adsorbents

To obtain an edible grade of soybean oil, impurity removal processes are important steps in refining. To remove coloring compounds and free fatty acids, commercial adsorbents (silica gel, activated carbon, aluminum oxide, alumina silicate, acid clay, and zeolite) and rice hull silicate (RHS) were evaluated with respect to their adsorption removal efficiencies for lutein. Various doses of commercial adsorbents and RHS were individually added to degummed soybean oil to remove lutein. The commercial adsorbents and RHS substantially reduced lutein amounts in degummed soybean oil. Silica gel was the most effective adsorbent, followed by acid clay, and RHS. Treatments with adsorbents also reduced the residual free fatty acid (FFA) content. Aluminum oxide was the most effective in removal of FFA (approximately 40% reduction). RHS and rice hull ash (RHA) showed similar deacidification effects. RHS can be used as an alternative bleaching agent as it was effective in reducing the residual FFA content in soybean oil.     

稻壳真空烧结制备多孔炭材料研究

稻壳是稻米加工业的重要副产物。目前稻壳的深加工利用率低,因此开发以稻壳为原料的高附加值产品成为粮食深加工领域的一个热点问题。以稻壳为原料,经过预炭化后,采用一定浓度的碱溶液浸泡处理,然后真空烧结活化制备出了多孔炭材料。研究了预炭化工艺和活化条件对多孔炭材料的比表面积、孔结构及灰分的影响。结果表明:稻壳在马弗炉中300℃预炭化1h,然后采用10%KOH溶液浸泡24h,再700℃真空烧结1.5h得到的多孔炭产品比表面积达到1600cm2/g以上。     

Studies on the relationship between antioxidative activity of rice hull and germination ability of rice seeds

An investigation of the germination potentials of seeds of Indica and Japonica rice varieties revealed that while the long-life rice seeds retained the germination ability even on storage for a year at 30°C, the germination ability of the short-life rice seeds tended to decrease when stored beyond 6 months. The role of rice hull constituents in the preservation of the germination property during ageing of rice seeds was investigated with special emphasis on rice antioxidants. Antioxidative assay with chloroform-methanol and methanol-water extracts of hull, bran-germ and grain fractions of two Indica and five Japonica rice varieties indicated that all of the seed varieties belonging to Indica and Japonica possessed a strong antioxidative activity in the hull fraction. Hull extracts of long-life rice seeds showed relatively higher activities than those of short-life rice seeds. In contrast, hull extracts of long-life rice seeds had higher inhibitory effects on lipoxygenase activity than did those of short-life varieties. Quantification of the natural antioxidants indicated that ^α-tocopherol in rice oil to be present in the range of 318.3–450.1 μg g^?1 oil while the amount of oryzanol in the hull, bran-germ and grain fractions of rice was found to be 1.0–5.8, 95.4–279.8 and 3.0–9.4 μg g^?1 sample respectively. The results, however, did not show any positive correlation between the amount of natural antioxidants in rice hull and germination potentials of rice seeds. The amount of total phenolic constituents in rice hull was found to range from 190–390 μg g^?1 sample, the levels being far higher in long-life rice seeds in comparison with the short-life rice seeds. These values seemed to agree well with the germination data of the corresponding rice variety. The investigation revealed a strong influence of the level of phenolic constituents in rice hull on the storability of rice seeds.     

大豆皮利用的研究进展

大豆皮是大豆脱皮制油加工过程中的副产物。大豆皮富含纤维,除主要用作饲料外,可以经改性处理用作吸附剂,还可提取其中的有效成分,如膳食纤维、过氧化物酶等用于食品工业中。另外,大豆皮可以发酵生产燃料乙醇,还可以制作成锂离子电池的负极。大豆皮的利用途径很多,随着科技的发展,这一资源会得到充分的利用。     

改性大豆皮用于降低水硬度的研究

对大豆皮的改性方法及其处理水的过程进行了实验研究。对改性方法、改性剂和再生剂的选择进行了详细的实验，进而确定了改性剂、再生剂的最佳剂量及最佳反应时间。研究表明：大豆皮磺化改性后，对水中钙镁离子有很强的吸附作用，能够达到降低水硬度的目的；而大豆皮的再生实验也证明改性大豆皮可用作工业生产用水的软化处理。     

稻谷外壳拉伸力学性能实验研究

该研究运用TMS-Pro物性分析仪及自制仪器对稻谷外壳进行拉伸实验,测得稻谷外壳的力学特性参数及力-位移曲线,并结合稻谷外壳拉伸断裂裂纹处的显微图像分析稻谷外壳拉伸破坏过程。通过力-位移曲线和实验数据,得到稻谷外壳拉伸破坏前的力-位移回归方程,并通过对稻谷外壳的拉伸破坏力和弹性模量进行差异显著性分析,暨以探讨稻谷非正常破碎的原因及影响因素。     

新型磷脂酶用于米糠油酶法脱胶的研究

探讨了反应时间、柠檬酸添加量、酸碱配比、水洗和脱色等条件对米糠油酶法脱胶油含磷量的影响,得到以下优化条件:反应时间5 h,柠檬酸添加量0.06%,柠檬酸:NaOH为1:0.4,8 000r/min混合速度,3%白土脱色,在优化条件下酶法脱胶可使脱胶油含磷量降低至25 mg/kg左右,经过3%白土吸附脱色含磷量可降低至7 mg/kg以下,可以满足物理精炼的要求.另外,水洗可小幅度降低脱胶油含磷量;和其他植物油酶法脱胶相比,米糠油酶法脱胶对酸碱配比的要求相对较低.     

大豆油酶法脱胶和硅胶吸附脱皂效果研究

利用PLA1脱除大豆毛油中的磷脂,再用硅胶吸附脱除大豆油中的残磷和残皂。以酶法脱胶后含磷量、硅胶吸附脱皂后的含磷量和含皂量为评价指标,研究酶法脱胶及硅胶吸附脱皂对大豆油脱胶脱皂效果的影响。结果表明：在大豆油pH 5.5～6、去离子水添加量3%、反应时间6～8 h的脱胶条件下,酶法脱胶效果随PLA1添加量的增加而提高,PLA1添加量分别为50、75、100 mg/kg时,脱胶大豆油中含磷量分别从566.36、538.02、562.76 mg/kg降至44.67、18.99、17.01 mg/kg,再添加油质量0.1%的SORBSIL R92硅胶,大豆油含磷量分别降至41.21、16.35、15.42 mg/kg,含皂量分别从37、23、14 mg/kg降至14、8、5 mg/kg。酶法脱胶后大豆油酸值和过氧化值有所升高,3个油样的酸值（KOH）平均升高0.63 mg/g,过氧化值平均升高0.007 g/100 g。硅胶吸附脱皂也造成大豆油酸值和过氧化值有所升高。     

Use of some agricultural waste hull ashes for the regeneration of fried sunflower oil

The present study was aimed at improving the quality of fried sunflower oil. Synthetic (Magnesol XL), natural (diatomaceous earth) and hull ashes of rice, wheat and barley (agriculture plant wastes) were used to adsorb the oxidation products of fried sunflower oil. The mineral pattern (Si, Mg, Ca, Fe, Al, Mn and Cu) of the aforementioned substances were determined. The physico-chemical properties [refractive index, viscosity, colour, smoke point, acid value, peroxide value, thiobarbituric acid (TBA) value, conjugated dienes and trienes, polar content, polymer content and oxidised fatty acids] of non-fried, fried and fried-treated sunflower oil were determined. The frying process was carried out at 180 °C ± 5 °C for 20 h, 4 h heating cycle per day for five consecutive days. The fried sunflower oil was treated with synthetic, natural and agricultural hull ashes at 105 °C for 15 min. The results indicate that Magnesol XL, diatomaceous earth, rice hull ash, wheat hull ash and barley hull ash contained Si + Mg + Mn, Si + Mn + Ca, Si + Mn, Si +Mn and Mn + Si as the basic metals, respectively. Frying of sunflower oil led to significant increase in refractive index, viscosity, colour, smoke point, acid value, peroxide value, TBA value, conjugated dienes and trienes, polar content, polymer content, and oxidised fatty acids and decrease in iodine value. Treatments of fried sunflower oil with the aforementioned substances greatly improved the quality of fried oil. Under the present experimental conditions all adsorbing substances performed similarly in removing the fried sunflower oil oxidation products.     

Optimization of magnetic immobilized phospholipase A1 degumming process for soybean oil using response surface methodology

This study focused on optimization of processing conditions of enzymatic degumming process for soybean oil using phospholipase A₁ immobilized onto magnetic nanoparticles. A response surface methodology was developed and used to obtain optimum processing conditions. Four variables (temperature, reaction time, enzyme dosage, and added water) were investigated based on two response functions (phosphorus and free fatty acids (FFA) contents in degummed soy oil). For each response, second-order polynomial models were developed using multiple linear regression analysis. The optimum operating parameters of enzymatic degumming process were as follows: temperature of 56 °C, reaction time of 6.3 h, enzyme dosage of 0.10 g/kg, and added water of 2.13 ml/100 g. According to these optimum conditions, final residual phosphorus and FFA contents of degummed soy oil were reduced, respectively, to 10.38 mg/kg and 1.09/100 g using magnetic immobilized phospholipase A₁. This finding is applicable for the physical refining of soybean oil or refining crude oils from field- and frost-damaged beans which have high content of non-hydratable phosphatides.     

Preparation of low-fat uptake frying batter composite by dry particle coating of microparticulated soybean hull

This study examined the influence of soybean hull-coated frying batter composite on fat uptake during deep fat frying. Soybean hull was microparticulated by impact mill at impact mill speed (IMS) of 6000, 10,000 and 14,000 rpm, and air-classified into coarse and fine fractions at Air Classifying Wheel Speed (ACWS) of 4000, 8000 and 12,000 rpm, respectively. Each soybean hull was dry-coated into wheat flour by dry particle coating system. As the difference in particle size between wheat flour and soybean hull got larger, the coating process became more effective, which indicates the size difference between wheat flour and soybean hull was important for coating effectiveness. When the ratios of wheat flour to soybean hull were 99:1 and 95:5, there were about 3.3 (g/100 g) and 24.4 (g/100 g) of fat content reduction, respectively. Inner crust structures showed slight reduction in cell size and improved cellular integrity with shrinkage in the cell membrane, with increase in soybean hull content. This means soybean hull can form a protective layer and can be applied to the food industry as a frying batter composite to reduce fat uptake.     

花生皮壳的综合利用

花生是我国的主要油料作物和经济作物,花生皮壳是花生加工中的副产物,通常被当作饲料和燃料使用,造成了资源的浪费.如何将这一废物资源充分合理的开发利用,对于提高花生的经济效益和保护环境都有重要意义.通过对花生皮壳主要成分的分析可知,花生皮壳中含有丰富的粗纤维、碳水化合物、蛋白质,花生壳中还含有一些矿物质及药用成分等,花生皮中含有原花青素、白藜芦醇、维生素K等生物活性物质.由于这些物质的存在,使花生皮壳在化工、医药、食品、饲料等方面都具有开发利用价值.     

超声提取豆皮水溶性膳食纤维的工艺研究

利用响应面分析法优化超声豆皮水溶性膳食纤维（SDF）的提取工艺。在将豆皮高温预处理的基础上进行超声提取的单因素试验,根据中心组合试验设计原理,选定超声功率、超声时间和超声温度3个因素为响应因子,以豆皮SDF得率为响应值建立二次回归方程,相关系数R2=0．9733,通过响应面分析及岭脊分析得到豆皮SDF的优化提取条件。试验结果表明：当超声功率为491．5W、超声时间为26．5min、超声温度为62．6℃时,豆皮SDF的得率可达到最大,在此条件下,理论响应值为34．91％,验证值为35．22％。     

ADSORPTION EFFICIENCY OF SELECTED ADSORBENTS IN SESAME OIL MISCELLAS

In a sesame oil miscella (40% and 60%) system the adsorption efficiency for free fatty acids (Q_FFA.) and carotenoids (Q_c) provided by pine wood carbon (also known as vegetable carbon), two commercial synthetic silica adsorbents, and rice hull ash were compared at different adsorbent dosages (1.0, 2.5 and 5.0%).
At all the adsorbent dosages investigated the pine wood carbon achieved a higher Q_FFA than synthetic silicas and rice hull (P < 0.05). This effect was more evident as the carbon concentration decreased (P < 0.05). However, in the case of carotenoids none of the adsorbents exhibited a significant advantage in Q_c (P < 0.50) at any of the adsorbents dosages utilized. Rice hull ash had the highest oil retention, while silicas exhibited an oil retention profile with lower values than that obtained with pine wood carbon (P < 0.10). The results suggest that pine wood carbon might have the same capability as silicas when used with sequential addition of clay in sesame oil miscella refining, with the advantage of higher adsorption efficiency than silicas for free fatty acid adsorption.     

Development of Chinese steamed bread enriched in bioactive compounds from barley hull and flaxseed hull extracts

Hull from cereal and oilseed grains represent low-cost agricultural materials that have not be fully explored as functional food ingredients. The objectives of the present study were to investigate the phytochemical profile and antioxidant activity of Chinese steamed bread (CSB) containing extracts of barley hull and flaxseed hull. HPLC and LC–MS/MS analyses showed that the phytochemical profile of CSB containing barley hull extract was enriched in ferulic and p-coumaric acids. The flaxseed hull extract introduced secoisolariciresinol diglucoside (SDG), ferulic acid glucoside (FeAG) and coumaric acid glucoside (CouAG) into CSB. All the major phenolic compounds originating from the two types of hulls were found in CSB when barley–flaxseed hull co-extracts were added to the formulation. The total phenolic content was improved by 83.1, 138.3 and 70.3%, respectively when barley, flaxseed, and barley–flaxseed hull extracts were added. The antioxidant activity of CSB containing hull extracts was increased by 34.5–90.7% compared to the control. CSB containing hull extracts had significantly higher (p < 0.05) DPPH radical scavenging activity compared to the control. However, barley–flaxseed hull co-extracts resulted in the highest enhancement of ORAC values of the CSB, although no significant differences were found (p < 0.05). The findings indicate that extracts from barley hull, flaxseed hull and barley–flaxseed can be targeted for development as functional food ingredients that can enhance the phytochemical content of refined flour products, such as steamed bread.     

Effect of Various Pyrolysis Parameters on the Fragmentation Patterns of Peanut Oil

A simple and rapid pyrolysis-gas liquid chromatographic technique to quantitate the fragmentation pattern of a commercial peanut oil was developed. The oil was pyrolyzed at 300, 500, 700, 900, and 1100°C for 4, 10, and 16 sec. The optimum condition was determined by analyzing aliquots of the pyrolyzates by gas liquid chromatography and by quantitating data from 16 peaks. The operating parameters selected for optimum pyrolysis were 700°C for 10 sec under N₂ gas and 360 mm Hg partial pressure. Preliminary tests showed that this condition could be extended to other fats and oils.     

新型吸附剂稻壳灰性能研究

综述了稻壳灰经酸、水洗涤处理对游离脂肪酸和胡萝卜素的吸附性能 ,以及其他因素对吸附性能的影响。     

Characteristics of flaxseed hull oil

Oils from two commercial flaxseed hulls extracted by six procedures were evaluated for physicochemical characteristics. Oil yield ranged from 9% to 28% depending on solvent and extraction. Lipid fractionation of crude flaxseed hull oil yielded 92.5% neutral lipids, 3.1% phospholipids, 2.4% acidic lipids and 2.1% free fatty acids. Flaxseed hull oil exhibited three thermal transitions between −35 and −13 °C with solvent dependent polymorphism. Thermal oxidation by differential scanning calorimetry (DSC) revealed three step oxidation of flaxseed hull oil with mean onset and oxidation temperatures at 121 and 150–253 °C, respectively depending on the extraction procedure. Flaxseed hull oil exhibited two-fold difference (0.6–1.2 μm Trolox equivalent/g) in antioxidant activity measured by a photochemiluminescence (PCL) assay. Supercritical CO₂ extracted the most oil with the highest antioxidant capacity of all evaluated procedures resulting in a defatted flaxseed hull containing the highest (53 mg/g) secoisolariciresinol diglucoside (SDG) level.     

Polar compounds distribution of sunflower oil as affected by unsaponifiable matters of Bene hull oil (BHO) and tertiary-butylhydroquinone (TBHQ) during deep-frying

Total polar compounds (TPC) contents of the sunflower oil (SFO) increased linearly (R² > 0.99) with frying time. At the same concentration (100 ppm), the increase rate of the TPC content for the SFO containing the unsaponifiable matters (USM) of the Bene hull oil (BHO) was lower than that for the SFO containing the tertiary-butylhydroquinone (TBHQ). The TPC analysis by high-performance size-exclusion chromatography allowed the separation and quantification of triglyceride polymers (TGP), triglyceride dimers (TGD), oxidised triglyceride monomers (oxTGM), diglycerides (DG), and free fatty acids (FFA) during frying. The ability of the USM to resist the TGP formation was higher than that of the TBHQ. The USM and TBHQ showed lower influences on the changes in TGD and oxTGM contents, as well as there was an effectiveness better for the USM than for the TBHQ. The increase rate of DG and FFA contents more effectively decreased by the USM rather than by the TBHQ.