A Comparison of the Levels of Oil,Carotenoids, and Lipolytic Enzyme Activities in Modern Lines and Hybrids of Grain Sorghum

Carotenoids are potentially valuable components in grain sorghum and there is a need to better understand their concentration, composition, and value. Thirteen modern commercial grain sorghum hybrids and five sorghum lines were extracted and analyzed and the levels of oil and carotenoids were compared. The same samples were also evaluated for lipolytic enzyme activity. The oil content in all eighteen samples ranged from 3.21 to 4.29 wt%. Lutein and zeaxanthin were the predominant carotenoids and the levels of total carotenoids ranged from 3.82 to 19.5 ppm in the oil, which was much lower than the levels of total carotenoids in two yellow corn samples (70.8 and 103 ppm). Lipolytic enzyme activity was estimated by storing milled kernel samples for 2 weeks at 25 °C and measuring the levels of total free fatty acids. After 2 weeks, the levels of free fatty acids in the oil of the eighteen sorghum samples ranged from 11.49 and 52.17 wt%, compared to 10.29 and 17.54 wt% in oil from the two corn samples. This new data will be useful for persons using grain sorghum for food, biofuels and other industrial applications. Examples of sorghum genotypes with high and low levels of carotenoids and high and low levels of lipolytic enzymes were both identified.     

A Process for the Aqueous Enzymatic Extraction of Corn Oil from Dry Milled Corn Germ and Enzymatic Wet Milled Corn Germ (E-Germ)

A bench-scale aqueous enzymatic method was developed to extract corn oil from corn germ from either a commercial corn dry mill or corn germ from a newly-developed experimental enzymatic wet milling process (E-Germ). With both types of germs, no oil was extracted when acidic cellulase was the only enzyme used. Pre-treating dry milled corn germ by heating it in boiling water or microwave pretreatment, followed by enzymatic extraction with the acidic cellulase resulted in oil yields of about 43% and 57%, respectively. A two-step process, combining both acidic cellulase and alkaline protease treatments, with no heat pretreatment, achieved oil yields of 50–65% from dry milled corn germ and 80–90% from E-Germ. Mention of trade names or commercial products in this publication is solely for the purpose of providing specific information and does not imply recommendation or endorsement by the U.S. Department of Agriculture.     

Foam Separation of Oil from Enzymatically Treated Wet-Milled Corn Germ Dispersions

More than 9 billion gallons of ethanol were produced in 2008, mostly from dry grind corn fermentation plants. These plants are a potential source of substantial amounts of corn oil, if an economical method of separating it can be developed. In this work, oil was separated from corn germ by aqueous enzymatic extraction (AEE). Batches of wet-milled corn germ in water were preheated in a pressure cooker, ground in a colloid mill, and churned in a vertical column/mixing vessel system, after the addition of enzyme. Nitrogen gas was then bubbled through the column removing an overflowing foam fraction which was subsequently centrifuged to separate free oil. Using a newly commercialized enzyme complex it was found that 80% of the oil could be recovered using a w/w ratio of enzyme solution to germ of 1:80. The low dose and low price of the enzyme complex leads to a cost estimate of AEE of corn oil from germ, similar to the wet-milled germ extracted, cost competitive with expelled oil (with the separation and drying of the foam protein), and feasible for commercialization in a dry grind plant retrofitted to separate germ.     

Using Microwave Heating and Microscopy to Estimate Optimal Corn Germ Oil Yield with a Bench-Scale Press

The increase in ethanol production from corn has prompted development of processes to separate corn germ. The corn germ co-product would be a source of corn oil if a practical oil separation process were also developed. We carried out bench-scale corn-germ-pressing experiments to determine the maximum potential oil recovery which were then used to estimate commercial germ crushing costs. Corn germ was preheated in a microwave oven and oil was then extracted with a bench-scale press. Preheating the germ was necessary to obtain good oil yields. The uniform heating of the microwave oven more closely resembles compressive heating of commercial scale presses than does oven heating. Three different microscopic techniques were used to examine the effects of microwave and conventional-oven heating on corn germ. Microscopy revealed that microwave heating heated oil in the germ more quickly than the other components of the germ. Heating by both methods destroyed lipid body membranes and oil coalesced and pooled. Less oil could be pressed from germ initially containing 3–6% moisture than germ containing 15–20% moisture. Maximum oil recovery of about 65% was obtained for all germs tested when the optimum press temperature and germ feed moisture were used. Mention of trade names or commercial products in this publication is solely for the purpose of providing specific information and does not imply recommendation or endorsement by the US Department of Agriculture.     

Comparison of Carotenoids for Their Antifibrogenic Effects in Hepatic Stellate Cells

Hepatic stellate cells (HSC) have an important role in the development of liver fibrosis by producing extracellular matrix proteins when they are activated upon liver injury. We previously demonstrated that astaxanthin (ASTX), a xanthophyll carotenoid, attenuates HSC activation. The objective of this study was to compare the anti-fibrogenic effects of ASTX with those of other common carotenoids. LX-2 cells, a human HSC cell line, were treated with ASTX, lycopene, lutein (LT), zeaxanthin, or canthaxanthin, to measure messenger RNA (mRNA) and protein expression of pro-fibrogenic genes. Pro-fibrogenic gene expressions were also measured in ASTX- or LT-treated primary mouse HSC. To determine the underlying mechanisms of the anti-fibrogenic effect of ASTX and LT, SMA-related and MAD-related protein 3 (SMAD3) pathways and the accumulation of reactive oxygen species (ROS) were measured in LX-2 cells. Among five carotenoids tested, ASTX and LT attenuated HSC activation in LX-2 cells by reducing the mRNA and protein levels of pro-fibrogenic genes, such as smooth muscle α actin and procollagen type I α1 (COL1A1). In addition, both ASTX and LT significantly decreased the expression of pro-fibrogenic genes, including COL1A1, COL3A1, and COL6A1, in activated primary mouse HSC, with ASTX being more potent than LT. The anti-fibrogenic effect of ASTX was mediated by inhibiting the phosphorylation of SMAD3 and cellular ROS accumulation, while LT only prevented the accumulation of ROS in LX-2 cells. In conclusion, ASTX showed the most potent anti-fibrogenic effect among the five carotenoids via inhibition of SMAD3 phosphorylation and cellular ROS accumulation while LT only prevented ROS levels in HSC.     

Comparison of the Rancimat and the ACL Instrument for Measuring the Oxidative Stability of Corn Oil

A comparison was undertaken between two machines that utilise accelerated methods to measure oxidative stability: the Rancimat (Metrohm, Switzerland) and the single channel chemiluminescence instrument (ACL Instruments, Switzerland). The results from the machines showed good correlation for the measurement of the oxidation induction time of corn oil. For the ACL Instrument, the effect of the sample holder material (aluminium or borosilicate glass) was also investigated and clear differences were noted. Finally, a stability study was carried out over a period of 6 months, with corn oil, stored in the dark at three temperatures: ~4, ~27, ~40 °C and it was observed that it was possible to track subtle changes in oxidative stability using chemiluminescence.     

Fatty Acid,Phytosterol, and Polyamine Conjugate Profiles of Edible Oils Extracted from Corn Germ,Corn Fiber,and Corn Kernels

This study compared the profiles of fatty acids, phytosterols, and polyamine conjugates in conventional commercial corn oil extracted from corn germ and in two “new-generation” corn oils: hexane-extracted corn fiber oil and ethanol-extracted corn kernel oil. The fatty acid compositions of all three corn oils were very similar and were unaffected by degumming, refining, bleaching, and deodorization. The levels of total phytosterols in crude corn fiber oil were about tenfold higher than those in commercial corn oil, and their levels in crude corn kernel oil were more than twofold higher than in conventional corn oil. When corn kernel oil was subjected to conventional degumming, refining, bleaching, and deodorization, about half of the phytosterols was removed, whereas when corn fiber oil was subjected to a gentle form of degumming, refining, bleaching, and deodorization, only about 10% of the phytosterols was removed. Finally, when the levels of polyamine conjugates (diferuloylputrescine and p-coumaroyl feruloylputrescine) were examined in these corn oils, they were only detected in the ethanol-extracted crude corn kernel oil, confirming earlier reports that they were not extracted by hexane, and providing new information that they could be removed from ethanol-extracted corn kernel oil by conventional degumming, refining, bleaching, and deodorizing.     

Effect of Moisture and Heat Treatment of Corn Germ on Oil Quality

The changes in the quality of crude corn oil caused by moisture and two different thermal pretreatments (oven heating and steam heating) of wet‐milled corn germ were evaluated and compared with those of untreated oil. Increasing the moisture content of the corn germ from 8 to 25% before oil extraction increased the acid value (AV) (3.02–4.01 mg KOH g^?1), peroxide value (PV) (0.52–1.05 meq kg^?1), and the red value (7.3–8.7) and decreased the content of total tocopherols by 37% and that of γ‐tocopherols by 31%. Oven heating tended to decrease the AV and PV while steam heating significantly increased the total and individual tocopherol contents (P < 0.05). The different moisture contents and thermal pretreatments of corn germ caused no significant differences in the fatty acid composition and the contents of total and individual phytosterols of the crude oils. The γ‐tocopherol contents were found to be highly correlated with the red values (the corresponding R² reached 0.9977 and 0.9089 for moisture and heat pretreatments, respectively).     

Frying Stability of Canola Oil Blended with Palm Olein, Olive, and Corn Oils

The fatty acid composition, peroxide value (PV), acid value (AV), iodine value (IV), total tocopherols (TT) content, and total phenolics (TP) content of canola oil (CAO), palm olein oil (POO), olive oil (OLO), corn oil (COO), and the binary and ternary blends of the CAO with the POO, OLO, and COO were determined. The blends were prepared in the volume ratios of 75:25 (CAO/POO, CAO/OLO, CAO/COO) and 75:15:10 (CAO/POO/OLO, CAO/POO/COO). The CAO and its blends were used to fry potato pieces (7.0 × 0.5 × 0.3 cm) at 180 °C. During the frying process, the total polar compounds (TPC) content, AV, oil/oxidative stability index (OSI), and color index (CI) of the CAO/blends were measured. In general, frying stability of the CAO was significantly (P < 0.05) improved by the blending, and the frying performance of the ternary blends was found to be better than that of the binary blends.     

超声波辅助提取万寿菊中叶黄素的工艺研究

叶黄素是一种重要的抗氧剂,对视力有很好的保护作用。万寿菊花瓣中的叶黄素含量很高,是叶黄素提取的理想原料。超声波的空化效应可以破坏植物细胞而使溶剂渗透入植物细胞,加速细胞内物质的释放以达到缩短提取时间和提高提取效率的目的。本实验主要考察超声时间,超声功率,提取温度和料液比等因素对叶黄素提取效率的影响。     

Effects of Deuterium Oxide on the Oxidative Stability and Change of Headspace Volatiles of Corn Oil

Effects of deuterium oxide and deuterium oxide-free water on the oxidative stability and formation of headspace volatiles were determined for corn oils to evaluate the role of moisture as an active influential factors during lipid oxidation. Mixtures of corn oil and water with different ratios of deuterium oxide were prepared, and the mixtures were stored at 60 °C for 2 days. Headspace oxygen contents, conjugated dienoic acid (CDA) values, and p-anisidine values (p-AV) were analyzed as a measure of oxidative stability, and headspace volatiles were analyzed by solid phase microextraction and a gas chromatography mass selective detector to determine the involvement of deuterium in volatiles. Deuterium oxide accelerated the rate of lipid oxidation in corn oil compared to oils with deuterium-free water based on the results of headspace oxygen content, CDA, p-AV, and total volatile content. Fragmented mass to charge ratios (m/z) of 73.1/72.1 for d ₁-pentane/pentane and 57.0/56.0 for d ₁-2-propenal/2-propenal from samples containing deuterium oxide were significantly higher than those from deuterium oxide-free water, implying that moisture participated to form volatiles in corn oil oxidation under air-tight condition. Deuterium oxide appeared to accelerate the rate of lipid oxidation in corn oils and participated to form volatiles from oils during oxidation.     

含有植物纤维或玉米淀粉的食品接触产品质量安全风险研究

研究市售的含有植物纤维或玉米淀粉的食品接触产品质量状况并对其安全性进行初步评价。参考标准要求并结合可能存在的质量安全隐患,从傅里叶变换红外(FTIR)材质分析、总迁移量、重金属(以Pb计)、脱色试验、五氯苯酚特定迁移量及砷、镉、铬、铅含量等维度对含有植物纤维或玉米淀粉的食品接触产品进行研究。35批次样品中有2批次塑料主体材质为密胺,2批次塑料主体材质为聚乳酸,31批次塑料主体材质均为聚丙烯;35批次样品的重金属(以Pb计)、脱色试验、五氯苯酚特定迁移量等项目均符合所参照标准的要求;35批次样品均检出至少含2种重金属,有4批次一次性淀粉餐具总迁移量超标。从检验结果可知,市面上销售的含有植物纤维或玉米淀粉的食品接触产品存在总迁移量超标及样品含重金属的情况,说明市场上该类产品确实存在一定的潜在风险。     

Bioactive Compounds,Antioxidant Activities and Heat Stability of Corn Oil Enriched with Tunisian Citrus aurantium L. Peel Extract

This study was designed to examine physicochemical composition, antioxidant activities and heat stability of corn oil enriched with bitter orange peel. Volatile compounds composition of corn oil flavored with Citrus aurantium peel was investigated. Flavored oil total aroma content (2.6 mg/mg oil) was mainly represented by monoterpene hydrocarbons and limonene was the major one (2.49 mg/mg oil). Flavored oil methanolic extract was characterized by total phenol content of 1.22 mg GAE/kg. Chlorogenic, ferulic and p-coumaric acids were the major phenolic components of the flavored oil extract (34.33, 30.24 and 19.39 %, respectively). It was also characterized by a higher chlorophylls and carotenoids contents than the refined one. Antioxidant activities of methanolic extracts of both samples were determined using four assays: DPPH, reducing power, β-carotene bleaching and metal chelating tests. In β-carotene bleaching and DPPH radical scavenging assays, flavored oil methanolic extract showed higher activities than the control. It was characterized by a total antioxidant activity of 4.08 mg GAE/kg and an EC₅₀ value of 3.14 mg/mg oil. Its concentration providing 50 % inhibition (IC₅₀) was 0.53 mg/mg oil in the DPPH test and 4.08 mg/mg oil in the β-carotene bleaching test. However, refined corn extract showed significantly lower antioxidant activities (p < 0.05). Results of the oxidative stability index showed bitter orange peel effectiveness against thermal oxidation based on the increased induction time observed in flavored oil (5.95).     

Testing the Antioxidant Effect of Essential Oils and BHT on Corn Oil at Frying Temperatures: a Response Surface Methodology

Food habits worldwide have increased the demand for oxidative-resistant oils that can be used for deep-frying. Oxidative stability in oils can be improved by changing the fatty acid composition of the oil or by adding natural antioxidants to the oil. In this study, the effect of essential oils of seven plants; cinnamon, rosemary, sage, turmeric, clove, thyme and oregano enriched with carvacrol on the oxidative stability of corn oil at frying temperatures were studied. Experiments were conducted by using a PetroOxy device, a rapid small scale oxidation stability test. A central composite design was used to evaluate the effects of concentration of essential oil (X1: 1,500–5,000 ppm) and temperature (X2: 150–180 °C), on the induction time of corn oil. In order to compare the results with the synthetic antioxidant, butylated hydroxy toluene (BHT), another design was made with a concentration range (60–350 ppm) containing the legal upper limit of BHT, 200 ppm. Induction periods obtained from the accelerated oxidation test revealed that increasing temperature decreased the induction time of all the samples. However, the essential oils except for oregano oil had no significant antioxidative effect on corn oil, probably due to a lower content of their active components. The antioxidative effect of oregano oil was also found to be higher compared to BHT. At very high temperatures (e.g., 180 °C), the concentration of antioxidants had no effect on the induction periods.     

Impact of Sequential Ammonia Fiber Expansion (AFEX) Pretreatment and Pelletization on the Moisture Sorption Properties of Corn Stover

Combining ammonia fiber expansion (AFEX?) pretreatment with a depot processing facility is a promising option for delivering high-value densified biomass to the emerging bioenergy industry. However, because the pretreatment process results in a high moisture material unsuitable for pelleting or storage (40% wet basis), the biomass must be immediately dried. If AFEX pretreatment results in a material that is difficult to dry, the economics of this already costly operation would be at risk. This work tests the nature of moisture sorption isotherms and thin-layer drying behavior of corn (Zea mays L.) stover at 20°C to 60°C before and after sequential AFEX pretreatment and pelletization to determine whether any negative impacts to material drying or storage may result from the AFEX process. The equilibrium moisture content to equilibrium relative humidity relationship for each of the materials was determined using dynamic vapor sorption isotherms and modeled with modified Chung-Pfost, modified Halsey, and modified Henderson temperature-dependent models as well as the Double Log Polynomial (DLP), Peleg, and Guggenheim Anderson de Boer (GAB) temperature-independent models. Drying kinetics were quantified under thin-layer laboratory testing and modeled using the Modified Page's equation. Water activity isotherms for non-pelleted biomass were best modeled with the Peleg temperature-independent equation while isotherms for the pelleted biomass were best modeled with the Double Log Polynomial equation. Thin-layer drying results were accurately modeled with the Modified Page's equation. The results of this work indicate that AFEX pretreatment results in drying properties more favorable than or equal to that of raw corn stover, and pellets of superior physical stability in storage.     

Thermal Degradation of p-Hydroxybenzoic Acid in Macadamia Nut Oil,Olive Oil,and Corn Oil

p-Hydroxybenzoic acid (PHBA) plays a significant role in sustaining the oxidative stability of macadamia nut oil (MNO). However, PHBA undergoes thermal decarboxylation and loses its bioactive antioxidant properties. In this study, we determine PHBA degradation kinetics in oils at various heating temperatures, which provides fundamental understanding of PHBA thermal degradation in oils and oil quality changes during high-temperature processing. PHBA degradation kinetics in MNO, olive oil, and corn oil were evaluated at temperatures typical for cooking and frying. PBHA headspace concentration was measured using selected ion flow tube mass spectrometry. PHBA decarboxylation followed a zero-order reaction, where degradation could be affected by factors such as the type of oil matrix having different FA compositions, antioxidants, and component interactions. PHBA degradation activation energies (E _a) showed that PHBA was more stable against thermal decarboxylation in MNO (85 kJ mol^–1) than in olive oil (40 kJ mol⁻¹) or corn oil (22 kJ mol⁻¹). The higher enthalpy () of decarboxylation in MNO (82 kJ mol⁻¹) indicates that PHBA is more inhibited from decomposition than olive oil (37 kJ mol⁻¹) or corn oil (19 kJ mol⁻¹). Moreover, the negative entropy values () of PHBA degradation from MNO (−192 J mol⁻¹ K⁻¹), olive oil (−277 J mol⁻¹ K⁻¹), and corn oil (−325 J mol⁻¹ K⁻¹) indicates that these oils impart some inhibitory properties against PHBA thermal decarboxylation.     

The Optimization of the Production of Methyl Esters from Corn Oil Using Barium Hydroxide as a Heterogeneous Catalyst

In recent years, vegetable oils, as renewable raw materials, became a promising feedstock for chemicals and biodiesel production. The main products derived from oils are esters of fatty acids, especially methyl esters, obtained by their transesterification with methanol, in presence of acid or alkaline catalysts. The use of such catalysts implies the need for washing operations, which leads to environmental pollution. In the present paper, the response surface methodology based on a central composite design, has been developed to optimize the process of transesterification of corn oil. Ba(OH)₂ in presence of diethyl ether was used as catalyst. A quadratic polynomial equation was obtained. It correlates the reaction parameters [methanol/oil molar ratio (x _r), reaction time (x _t) and catalyst concentration (x _c)] with methyl esters yield. Analysis of variance analysis showed that only methanol/oil molar ratio and catalyst concentration have had the most significant influences on the conversion. The maximum methyl esters yield was obtained using the following optimum parameters: methanol/corn oil ratio of 11.32, reaction time of 118 min and catalyst concentration of 3.6 wt%.     

Effect of Compounds Affecting ABCA1 Expression and CETP Activity on the HDL Pathway Involved in Intestinal Absorption of Lutein and Zeaxanthin

The antioxidant xanthophylls lutein and zeaxanthin are absorbed from the diet in a process involving lipoprotein formation. Selective mechanisms exist for their intestinal uptake and tissue‐selective distribution, but these are poorly understood. We investigated the role of high‐density lipoprotein (HDL), apolipoprotein (apo) A1 and ATP‐binding cassette transporter (ABC) A1 in intestinal uptake of lutein in a human polarized intestinal cell culture and a hamster model. Animals received dietary lutein and zeaxanthin and either a liver X receptor (LXR) agonist or statin, which up‐ or down‐regulate intestinal ABCA1 expression, respectively. The role of HDL was studied following treatment with the cholesteryl ester transfer protein (CETP) modulator dalcetrapib or the CETP inhibitor anacetrapib. In vitro, intestinal ABCA1 at the basolateral surface of enterocytes transferred lutein and zeaxanthin to apoA1, not to mature HDL. In hamsters, plasma lutein and zeaxanthin levels were markedly increased with the LXR agonist and decreased with simvastatin. Dalcetrapib, but not anacetrapib, increased plasma and liver lutein and zeaxanthin levels. ABCA1 expression and apoA1 acceptor activity are important initial steps in intestinal uptake and maintenance of lutein and zeaxanthin levels by an HDL‐dependent pathway. Their absorption may be improved by physiological and pharmacological interventions affecting HDL metabolism.     

XY－4新型玉米淀粉粘合剂的研制

选用合适的催化剂、增粘剂和催干剂，不用加热，经快速催化氧化法制得了ＸＹ－４新型玉米淀粉粘合剂，使用时不用干燥设备。介绍了反应原理、原料配方、生产工艺、产品性能及影响质量的因素等。     

Extraction and Demulsification of Oil From Wheat Germ,Barley Germ,and Rice Bran Using an Aqueous Enzymatic Method

An aqueous enzymatic method was developed to extract oil from wheat germ. Wheat germ pretreatment, effect of various industrial enzymes, pH, wheat germ to water ratio, reaction time and effect of various methods of demulsification, were investigated. Pretreatment at 180 °C in a conventional oven for 4 min reduced the moisture 12.8–2.2 % and significantly increased the oil yield. Adding a combination of protease (Fermgen) and cellulase (Spezyme CP) resulted in a 72 % yield of emulsified oil from wheat germ (both commercial and laboratory milled wheat germ). Using the same oil extraction conditions optimized for wheat germ, yields of 51 and 39 % emulsified oil were obtained from barley germ (laboratory milled), and rice bran, respectively. Three physical demulsification methods (heating, freeze-thawing, and pH adjustment) and enzymatic methods (Protex 6L, Protex 7L, Alcalase, Fermgen, Lysomax and G-zyme 999) were compared. After demulsification with Protex 6L, free oil yields of 63.8 and 59.5 % were obtained with commercial wheat germ and with laboratory milled wheat germ, respectively. Using the same demulsification conditions optimized for wheat germ, yields of 45.7 % emulsified oil and 35 % free oil were obtained for barley germ and rice bran, respectively.