提取方法对奇亚籽油品质特性的影响

以奇亚籽为原料,分别采用压榨法、溶剂浸提法、水酶法和超临界CO₂萃取法提取奇亚籽油,对比分析不同方法提取奇亚籽油的理化性质、脂肪酸组成、油脂氧化稳定性、酚类物质含量及体外抗氧化能力等品质特性。结果表明:4种方法中,超临界CO₂萃取法的油脂得率最高(85.5%),其次是溶剂浸提法(65.8%)和压榨法(40.9%),水酶法最低(33.2%)。超临界CO₂萃取的奇亚籽油品质最佳,色泽为黄值70红值4.3灰值0.3,酸价为1.10 mg KOH/g、过氧化值为0.0137 g/100 g,含有不饱和脂肪酸总质量分数为88.22%,其中亚油酸18.36%,亚麻酸69.86%;其氧化速度最慢在30 h后过氧化值达到0.25 g/100 g;总酚含量为106.45 mg/kg,黄酮含量为222.09 mg/kg。超临界CO₂萃取的奇亚籽油在相同质量浓度下的DPPH自由基清除能力(IC₅₀ 28.04 mg/mL)与ABTS+·清除能力(IC₅₀ 33.70 mg/mL)优于压榨法、溶剂浸提法和水酶法;对超氧阴离子自由基清除能力(IC₅₀ 10.08 mg/mL)优于溶剂浸提法、水酶法,略低于压榨法。     

微波预处理对奇亚籽出油率及油脂品质的影响

采用微波技术对奇亚籽进行预处理后低温压榨制油,测定奇亚籽油理化指标、营养及抗氧化指标,探讨微波预处理条件对奇亚籽出油率以及奇亚籽油品质的影响。结果表明：原料的水分含量、微波时间、微波功率对奇亚籽出油率和奇亚籽油的理化指标、黄酮含量、多酚含量及DPPH·和O-2·清除能力均有一定的影响,对奇亚籽油脂肪酸相对含量影响较小。经单因素实验和正交实验得出：微波预处理奇亚籽的适宜工艺条件为奇亚籽水分含量12%、微波时间3 min、微波功率600 W,在该条件下奇亚籽出油率可达到21.05%,奇亚籽油酸价（KOH）0.52 mg/g、过氧化值0.44 mmol/kg、黄酮含量318.25 mg/kg、多酚含量28.00 mg/kg,DPPH·和O-2·清除率分别为2479%和26.84%。     

超临界CO_2萃取奇亚籽油工艺优化及抗氧化活性的研究

为高效地提取奇亚籽油,采用单因素及正交实验优化超临界CO_2萃取奇亚籽油最佳工艺条件,考察物料粒度、萃取压力、萃取温度以及萃取时间4个因素对奇亚籽油萃取率的影响,并对奇亚籽油进行抗氧化活性的测定。结果表明:超临界CO_2萃取奇亚籽油最佳工艺条件为物料粒度60目、萃取压力25 MPa、萃取温度50℃、萃取时间2.5 h,奇亚籽油萃取率为85.50%。奇亚籽油中富含不饱和脂肪酸,占总脂肪酸的88.22%,其中亚麻酸高达69.86%。抗氧化实验表明,奇亚籽油对DPPH自由基和ABTS~+自由基具有较强的清除作用,对超氧阴离子自由基也显示出一定清除效果。     

奇亚籽油的品质评价及其在魔芋糕中对小鼠血糖调节作用的影响

该文通过分析螺旋压榨奇亚籽油的理化性质、脂肪酸组成评价其品质,将奇亚籽油加入到魔芋糕中利用小鼠饲喂实验评价其降血糖效果。结果表明,奇亚籽油折光系数1.480 6,碘值194 g/100 g,皂化值190.1 mg KOH/g,不溶性杂质<0.01%,酸值0.55 mg KOH/g,过氧化值6 mmol/kg;奇亚籽油脂肪酸组成中α-亚麻酸和亚油酸分别占59. 35%、19. 59%且PUFA/SFA=7. 07。通过比较2组不同饲喂条件下(奇亚籽油魔芋糕组、不含奇亚籽油魔芋糕组)小鼠的体重、空腹血糖的指标,得出2组产品对小鼠体重调节作用无显著性差异(P>0.05),对小鼠空腹血糖调节作用存在显著性差异(P <0.05),饲喂后2组小鼠空腹血糖值分别为5. 98、6. 84 mmol/L(模型组为7. 99 mmol/L)。表明奇亚籽油魔芋糕对小鼠血糖调节作用更好,可为制备奇亚籽油及魔芋粉新型产品提供理论依据。     

金柚柚子籽油的制备及理化性质研究

以广东梅州金柚柚子籽为研究对象,采用有机溶剂浸提法对柚子籽中的油脂进行提取,分析其脂肪酸组成、酸价、过氧化值等理化指标,并采用顶空-固相微萃取-气相色谱-质谱(HSSPME-GC-MS)对柚子籽油的挥发性成分进行研究,同时对柚子籽粕中多肽、多糖、多酚和黄酮含量进行了测定。结果表明:柚子籽油得率为(55. 74±1. 25)%,柚子籽油不饱和脂肪酸含量高达68. 43%,主要是亚油酸((40. 45±0. 05)%)和油酸((23. 08±0. 03)%);柚子籽油中生育酚和角鲨烯的含量分别为(56. 04±0. 36)μg/g和(4. 22±0. 22)μg/g,酸价(KOH)((0. 86±0. 16) mg/g)、过氧化值((0. 63±0. 14) mmol/kg)均较低,且在国标限量范围内;柚子籽油共鉴定出57种挥发性成分,包括烃、醇、酸、酯、醛酮、酚和含氮类化合物,赋予了柚子籽油独特的柚子香味;柚子籽粕中多肽和多糖含量较高,分别为3. 50%和3. 90%,柚子籽粕中多酚和黄酮含量较低。     

奇亚籽油的品质特性及提取工艺研究进展

奇亚籽油富含不饱和脂肪酸,其中α-亚麻酸含量达60%以上,是ω-3脂肪酸的天然来源,对预防与饮食相关的慢性疾病具有重要意义。奇亚籽油中的抗氧化活性成分丰富,涵盖生育酚、植物甾醇、角鲨烯及多酚等。综述了近年来国内外有关奇亚籽油的脂肪酸组成、理化性质、提取工艺、氧化稳定性等领域的研究报道,并对奇亚籽油今后研究方向和重点进行了展望。     

响应面优化水酶法提取奇亚籽油工艺

以奇亚籽为原料,采用水酶法提取奇亚籽油。在单因素实验的基础上,采用响应面法对水酶法提取奇亚籽油的工艺条件进行优化。结果表明,水酶法提取奇亚籽油的最佳工艺条件为:碱性蛋白酶作为酶解用酶,酶解温度45℃,液料比8. 47∶1,pH 10,酶添加量5. 17%,酶解时间2. 16 h。在最佳条件下,奇亚籽油提取率为89. 53%。     

奇亚籽胶提取工艺优化及其理化性质

以奇亚籽为原材料,利用单因素和响应面试验对奇亚籽胶的提取工艺进行优化筛选。结果表明,最佳的提取工艺条件为料液比1∶45（g/mL）、浸提温度90 ℃、pH8.2。对奇亚籽胶理化性质的研究结果表明,奇亚籽胶具有良好的理化性能,其优异的持水/油、乳化、起泡等性质使其在肉制品、烘焙产品、乳制品等领域的应用前景较广。     

奇亚籽饼的营养成分分析及物性研究

为提高奇亚籽饼的利用率,对奇亚籽饼的营养成分进行分析评价,并对其物性进行研究。结果表明:奇亚籽饼中含有(32.70±0.10)g/100 g的粗蛋白质,(44.74±0.53)g/100 g的膳食纤维,残存脂肪(7.15±0.26)g/100 g;压榨过程中部分不饱和脂肪酸氧化分解为饱和脂肪酸;氢氧化钾蛋白质溶解度为90%,符合大豆粕国家标准要求;奇亚籽饼的多酚含量为4.67 mg/g,高于奇亚籽中的多酚含量(3.63 mg/g);经测定奇亚籽饼的膨胀力、持水力、结合水力、吸脂力,得出其综合物性值为11.60,优于常见的大豆纤维和玉米纤维,具有较好的减肥调脂、降血糖等功能特性。     

湘西猕猴桃籽成分分析及猕猴桃籽油的特性研究

分析了湘西猕猴桃籽的主要成分,同时采用水酶法提取猕猴桃籽油,并对猕猴桃籽油的特性进行了研究。结果表明:湘西猕猴桃籽粗脂肪含量32.19%,粗蛋白质含量16.06%;猕猴桃籽中氨基酸种类不全,缺少2种氨基酸,属于不完全蛋白质;鲜味谷氨酸(Glu)和天门冬氨酸(Asp)含量很高,分别为6.1 mg/g和3.5 mg/g,占氨基酸总量的25.98%,为猕猴桃籽增添了良好的风味;水酶法提取猕猴桃籽油总出油率为25.89%,萃取率达80.45%;猕猴桃籽油中亚麻酸含量高达60.59%,不饱和脂肪酸含量达89.92%,生育酚含量为812.41 mg/kg。     

Natural pigments: carotenoids, anthocyanins, and betalains--characteristics, biosynthesis, processing, and stability

Pigments are present in all living matter and provide attractive colors and play basic roles in the development of organisms. Human beings, like most animals, come in contact with their surroundings through color, and things can or cannot be acceptable based on their color characteristics. This review presents the basic information about pigments focusing attention on the natural ones; it emphasizes the principal plant pigments: carotenoids, anthocyanins, and betalains. Special considerations are given to their salient characteristics; to their biosynthesis, taking into account the biochemical and molecular biology information generated in their elucidation; and to the processing and stability properties of these compounds as food colorants.     

Hormones, metabolites, and reproduction in Holsteins, Jerseys, and their crosses

Holsteins (HH), Jerseys (JJ), and their crosses in first (n=157) and second (n=107) lactation were used to determine if reproduction, progesterone (P4), insulin-like growth factor 1 (IGF-1), insulin, nonesterified fatty acids (NEFA), and milk production differed between genetic groups. Thirty-four cows were Holstein-Jersey (HJ) crosses, 46 were Jersey-Holstein (JH) crosses, 48 were purebred Holsteins (HH), and 29 were purebred Jerseys (JJ) in first lactation, whereas the second-lactation animals included 23 HJ, 35 JH, 35 HH, and 14 JJ. Blood samples were collected weekly for the first 10 wk postpartum. Analyses were conducted using the MIXED, chi-square, and GLIMMIX procedures (SAS Institute Inc., Cary, NC). Seasons of calving were cold (November to May) and hot (June to October) and were combined with year to form 8 year-seasons. Days open and number of services were affected by genetic group. The HH were open 169±8 d, which was greater than HJ (143±9 d), JJ (132±10 d), and JH (127±8 d). The HH had 2.4±0.1 services per pregnancy, which was greater than JH (1.9±0.1), but not different from HJ (2.1±0.2) or JJ (2.1±0.2). Concentrations of NEFA were greater in lactation 2 (0.52±0.02 mEq/L) than in lactation 1 (0.45±0.02 mEq/L) and decreased over the 10-wk period. Concentrations of NEFA were greater in the cold season except in yr 3. Insulin in lactation 1 (0.81±0.03 ng/mL) was greater than in lactation 2 (0.72±0.03 ng/mL); insulin decreased to wk 2 then gradually increased. The HJ had the greatest insulin concentrations (0.87±0.04 ng/mL) and the JJ had the lowest (0.66±0.04 ng/mL), and IGF-1 gradually increased over the 10-wk period. Milk production (actual yield in the first 305 d, not adjusted for fat and protein) was affected by genetic group, lactation number, year-season, and wk 1 insulin. The HH produced 10,348±207 kg of milk, which was greater than the HJ (9,129±230 kg), the JH (9,384±190 kg), and the JJ (7,080±240 kg). Milk production in lactation 2 (9,676±163 kg) was greater than that in lactation 1 (8,294±160 kg). The JJ (10.3±4.7%) had the highest frequency of mastitis. The chance of getting mastitis for HH (1.1±0.9%) differed from that for HJ (9.4±4.1%), JH (8.1±3.4%), and JJ (10.3±4.7%). Genetic group affected hormones and metabolites, which may partially explain differences in reproductive measures and milk yield.     

Capsicum--production, technology, chemistry, and quality. Part V. Impact on physiology, pharmacology, nutrition, and metabolism; structure, pungency, pain, and desensitization sequences

The spice Capsicum is the fruit of the cultivated species of the genus Capsicum (family, Solanaceae), C. annuum principally, and C. frutescens L. to a lesser extent. A third variety of C. annuum var. annuum fruits, the large-sized, fleshy bell capsicum is used as a fresh vegetable and valued for its aroma, color, and crisp texture, but with no pungency. This variety is not considered in this series of reviews covering primary processing, production, international trade, chemistry, and biochemistry of functional components--the red keto carotenoids, the aromatic volatiles and the pungent capsaicinoids in Parts I to III. The valid qualitative aspects correlating the specific components of capsicum and their sensory responses are critically covered in Part IV. In this the concluding part of the series of reviews, the significant preference of the spice for initially evoking an aversive response, its potent physiological and pharmacological effects, and the aspects of structure-activity relationships of the pungent stimuli of the capsaicinoids are reviewed. The beneficial effects particularly associated with long usage by some ethnic groups and its safe consumption levels, with a critical review of the studies on the gastrointestinal tract, the cardiovascular system, the sensory system, thermoregulation, nutritional impacts, and an overview of the five series is also detailed.     

卷烟中锂、铬、镍、铜、砷、硒、钼、镉、铊和铅含量分析

采用微波消解-电感耦合等离子体质谱法测定了41个牌号烤烟型卷烟和雪茄烟样品烟丝中的锂、铬、镍、铜、砷、硒、钼、镉、铊和铅含量,并按照类型和价位对卷烟中这10种有害元素含量进行了统计分析。结果发现:①卷烟中锂和铜的含量较高,铊的含量很低,铬、镍、镉、铅、砷、硒和钼7种元素的平均含量为0.55～4.42μg/g;②雪茄烟中铬、镍、砷、钼、镉、铊和铅的含量一般高于烤烟型卷烟,而硒元素的含量则相反,但差别较小;烤烟型卷烟中锂和铜的含量与雪茄烟没有显著差异;③高档卷烟中的锂、镍、镉、铊和铬含量较低,而砷、铅的含量较高;不同价位卷烟的铜、硒和钼含量差异不显著。     

Simultaneous and Direct Determination of As, Bi, Pb, Sb, and Se and Co, Cr, Cu, Fe, and Mn in Milk by Electrothermal Atomic Absorption Spectrometry

Tungsten permanent modifier with coinjection of Pd(NO₃)₂ and W–Ru permanent modifiers are proposed for the direct and simultaneous determination of As, Bi, Pb, Sb, and Se (group 1) and Co, Cr, Cu, Fe, and Mn (group 2), respectively, in milk by graphite furnace atomic absorption spectrometry. The performance of modifiers was evaluated by means of thermal behavior of analytes, sensitivity, atomic signal profile, repeatability, graphite tube lifetime, and background intensity. An air-assisted pyrolysis step was necessary to quantitative elimination of the organic matter. After methods optimization, 14 commercial milk samples were analyzed. The found concentrations of As, Bi, Pb, Sb, Se, Co, and Cr were lower than their limit of detection (2.13, 2.21, 1.49, 1.63, 2.05, 1.0, and 1.2 μg L⁻¹, respectively). Concentrations of Cu, Fe, and Mn were in the 1.58–5.74 μg L⁻¹, 9.79–49.3 μg L⁻¹, and 2.25–4.08 μg L⁻¹ intervals, respectively. The limits of detection for Cu, Fe, and Mn were 1.7, 5.3, and 2.0 μg L⁻¹, respectively. The accuracy of methods was checked after analysis of two milk standard materials. Results for Cr, Cu, Fe, Mn, Pb, and Mn were in agreement with certified values of SRMs at the 95% confidence level. Accuracy was also evaluated by addition–recovery tests and recoveries in the 86–127% range were obtained for all elements. The use of pretreat platform of graphite tubes with W or W–Ru allowed enlarging the lifetime of atomizer in 750 heating cycles.     

Polyphenols, Anthocyanins, Ascorbic Acid, and Radical Scavenging Activity of Rubus, Ribes, and Aronia

ABSTRACT: Total polyphenols, total anthocyanins, and reduced ascorbic acid were evaluated in berries belonging to the genera Rubus, Ribes, and Aronia by means of spectrophotometric and high-performance liquid chromatography (HPLC) techniques. The 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity of the fruit extracts was tested. Total polyphenols ranged from 140.6 to 888.5 mg/100 g fresh weight (FW), total anthocyanins ranged from 22.0 to 460.5 mg/100 g FW, and reduced ascorbic acid ranged from 12.4 to 153.8 mg/ 100 g FW. The average EC50 values for Aronia melanocarpa, Ribes nigrum, Ribes rubrum, Rubus fruticosus, and Rubus idaeus were 1.8, 2.8, 5.3, 6.4, and 8.2 mg FW, respectively. The results indicate that the fruits tested are good sources of natural antioxidants.     

Tyrosinase, Laccase, and Peroxidase in Mushrooms (Agaricus, Crimini, Oyster, and Shiitake)

Enzyme assays and electrophoresis were used to monitor the activity of tyrosinase, laccase, and peroxidase in Agaricus bisporus (common cultivated button mushrooms and Crimini mushrooms), Oyster, and Shiitake mushrooms. The three enzymes could be differentiated using specific substrates and inhibitors. Tyrosinase seemed to be the major phenol oxidase in the Agaricus strains, while Oyster and Shiitake mushrooms had much lower levels. Peroxidase activity was low or undetectable in all types examined. Control of enzymatic browning in different mushroom types may depend upon the distribution of different oxidases within any given type.