鲜切荔枝果肉冰点调节工艺

研究了蔗糖、山梨醇、葡萄糖3种冰点调节剂对降低鲜切荔枝果肉冰点的效果及复配浓度的影响。在单因素实验的基础上,以鲜切荔枝果肉的冰点为响应值,通过响应曲面法建立回归模型,得到山梨醇、葡萄糖、蔗糖3种冰点调节剂的优化复配浓度为:山梨醇6.24%,葡萄糖7.31%,蔗糖40.93%。鲜切荔枝果肉经此优化复配浓度在3℃、浸渍3h处理后,其冰点可降至-4.15℃,与模型预测值(-4.13℃)接近,比未处理果肉的冰点降低了1.3℃。     

生姜在不同低温条件下的冻结规律及品质变化

对子姜在不同低温条件下的冻结曲线进行了测定,分析了以空气作为冷冻介质时子姜片的冻结规律,探讨了漂烫处理、冻结速度对产品质地的影响。实验结果表明,冷冻温度在-40℃以下可达到速冻要求;冻结前漂烫处理造成冰点上升,但在-40℃以下冻结时通过最大冰晶生成带的时间没有明显变化。     

冷鲜鸡胸肉复合冰点调节剂优化及其对冰点控制的研究

以确定冷鲜鸡胸肉的冰点温度,扩宽鸡胸肉冰点温度带为目的,对复合冰点调节剂进行优化研究。试验采用三因子五水平二次通用旋转组合试验设计方法,选取NaCl、山梨糖醇和麦芽糊精三种冰点调节剂为试验因子,以鸡胸肉冰点温度为指标建立数学模型,对鸡胸肉冰点调节剂最佳配比进行优化。结果表明,Na Cl可极显著降低鸡胸肉的冰点(p0.01),山梨糖醇、麦芽糊精可显著降低冰点(p0.05),NaCl与山梨糖醇、麦芽糊精分别存在协同交互作用。通过对模型进行优化分析,冰点调节剂的最佳配比为:Na Cl 5.42%,山梨糖醇7.36%,麦芽糊精10.36%。经冰点调节剂的调节,鸡胸肉冰点由-0.7℃降至-2.4℃,结果为冰温鸡肉加工及安全控制技术研究提供理论依据和技术支持。     

脆肉鲩低温相变区热特性的研究

采用差示扫描量热仪,研究脆肉鲩鱼肉在低温相变区的冰点、表观比热和热焓以及NaCl、NaCl 与蔗糖混合物添加量对脆肉鲩热特性的影响。结果表明,脆肉鲩鱼肉的冻结相变温区为－ 12.5～－ 11℃,熔融相变温区为－ 1.9～0.1℃,冰点为－ 0.2℃,冰点的表观比热和热焓值分别为130.56J/g·℃、305.57J/g。随着NaCl、NaCl和蔗糖混合物添加量的增加,脆肉鲩肌肉的相变温区向低温方向移动,冰点的表观比热和热焓值下降。鱼肉中NaCl添加量较低时,添加蔗糖可减缓相变温度的下降,当NaCl 添加量大于2% 时,添加蔗糖对鱼肉相变区温度的影响不大,NaCl 起主导作用。     

鲫鱼块冰点调节剂的研究

研究了不同冰点调节剂对鲫鱼块冰点的影响,并通过响应面优化设计对几种较好的冰点调节剂进行复配,较大幅度的降低了鲫鱼块的冰点.实验结果表明:氯化钙、山梨醇、氯化钠是较好的冰点调节剂,当山梨醇添加质量分数为1.74%,氯化钙添加质量分数为5.15%,氯化钠添加质量分数为2.13%时鲫鱼块的冰点降低到-1.6℃左右.     

鸡肉冰点调节剂的筛选及其贮藏期间品质变化

以新鲜鸡胸肉为原料,冰点为指标,采用响应面法对冰点调节剂的配比进行优化,并对冰鲜鸡肉贮藏期间品质变化进行研究。结果表明,筛选出冰点调节剂的最佳配方为:NaCl 5.48%、海藻糖3.12%、VC2.06%、山梨醇2.06%,在此条件下,预测鸡肉冰点为-2.4℃;在贮藏温度-2.4℃条件下,随着贮藏时间的延长,添加冰点调节剂的处理组在硬度、弹性、黏附性、咀嚼性和恢复性方面显著优于未添加冰点调节剂的对照组(P<0.05),且处理组有较高L*和a*、较低b*,保持了较好肉的色泽;贮藏期间处理组的挥发性盐基氮(total volatile basic nitrogen,TVB-N)上升值均低于对照组,其货架期可延长至24 d;扫描电镜(scanning electron micrograph,SEM)分析贮藏24 d鸡肉的微观结构表明,处理组的肉组织结构优于对照组,其肌原纤维结构未出现断裂、排列整齐且紧密。     

速冻方式与温度对鲍鱼品质的影响

为了研究不同速冻方式和冻结温度对鲍鱼冻结过程中的品质影响程度、产生原因及机理,本文以鲜活鲍鱼为研究对象,对比采用2种速冻方法(空气速冻和液体速冻)、3种冻结温度(-20℃、-40℃、-60℃)进行冷冻,以蛋白质冷冻变性程度、肌肉组织结构和弹性作为理化和质构特性评价指标。试验结果表明:液体速冻的冻结速率始终比空气速冻高10倍左右,盐溶性蛋白溶解度下降率低2%左右,Ca2+-ATPase活性下降速度与Mg2+-ATPase活性上升速度均略缓慢,蛋白质变性程度低,解冻后鲍鱼肌肉组织间空隙小,弹性好;冻结过程中,冻结温度越低,冻结速率越快,盐溶性蛋白损失越少,蛋白质变性程度和解冻后的弹性无明显变化;综合考虑冻结速率、品质、能耗等因素,认为液体速冻是适合鲍鱼的速冻方法,-60℃液体速冻是相对最佳的速冻工艺。     

直接浸渍冷冻草鱼块冻藏过程中品质变化研究

探讨直接浸渍冻结(immersion chilling and freezing,ICF)对食品冻藏品质的影响。以氯化钠、乙醇和丙二醇3种组分构成的多元载冷剂为冷冻介质(溶液温度－40℃)条件下草鱼块冻藏过程中品质的变化情况,并与空气鼓风式冻结(空气温度－ 40℃、风速6m/s)进行比较。结果表明：直接浸渍冻结其冻结速率是相同介质温度下空气鼓风式冻结的1.5 倍;冻结后的草鱼块中NaCl、乙醇和丙二醇的吸收量及总吸收量分别为0.14%、0.17%、0.63%、0.94%;相同冻藏条件下,直接浸渍冻结后的样品和传统的鼓风冻结后的样品相比,前者盐溶性蛋白含量高于后者,并且脂肪氧化程度、汁液流失和干耗均低于后者,直接浸渍冻结更有利于草鱼块冻藏过程中质构特性的保持。综合各指标说明直接浸渍冻结后的样品冻藏品质优于空气鼓风冻结。     

果汁冷冻浓缩过程中冰晶形成规律的研究

本研究测定了橙汁和菠萝汁的冰点曲线,并以此探讨在果汁冷冻浓缩时水分冻结率的变化规律。结果表明,果汁在开始冻结的温度附近结冰率变化最大;以后逐渐减慢。橙汁和菠萝汁的最大冰晶生成区分别是-0.8～-7.9℃和-0.7～-6.7℃。冷却介质温度越低,冰晶的生长速度越快,但最终冰晶尺寸越小。当介质温度为-10℃左右时,可获得较大的冰晶尺寸。本文也研究了搅拌作用及果汁预处理因素对冰晶生长的影响。     

高温蒸煮对鳙鱼块肌间小刺软化效果和质构品质的影响

以多肌间小刺的鳙鱼段为原料,以感官评定和质构为指标,研究经盐渍和热风干燥后,采用高温蒸煮处理对鱼肉肌间小刺软化的工艺条件。重点研究蒸煮温度、蒸煮时间、鱼块水分及盐分含量对高温蒸煮后的鳙鱼块肌间小刺软化效果和鱼肉质构品质的影响。结果表明:高温蒸煮温度、时间和鱼块水分含量为影响鱼肉肌间小刺软化和鱼肉质构品质的显著因素,盐含量影响不显著。经响应面优化,选择最佳高温蒸煮温度为126℃、时间26 min、水分含量48%,此时感官得分最佳,为9.89分。     

Concentrations of 21 metals in 18 species of mushrooms growing in the East Black Sea region

Eighteen different species of wild mushrooms (Agaricus bisporus, Agaricus silvicola, Amanita muscaria, Amanita rubescens, Amanita vaginata, Boletus sp., Hydnum repandum, Hypholoma fasciculare, Laccaria lacceta, Lactarius piperatus, Lactarius sp., Lactarius volemus, Pleurotus ostreatus, Russula cyanoxantha, Russula sp., Russula delica, Russula foetens andTricholoma terreum) growing in the East Black Sea region were analyzed spectrometrically for their metal element (Pb, Cd, Hg, Cu, Mn, Zn, Fe, Co, As, Ca, Na, K, Mg, Ba, Ni, Ti, Cr, Al, Bi, Sb, and Ag) levels. In the mushrooms, the highest metal concentrations were measured as 4.91, 3.48, 0.60, 92.5, 44.4, 176, 169, 0.72, 1.76, 106.4, 136, 51 000, 1320, 1.62, 145, 282, 1.68, 24.1, 1.84, 0.26, and 0.37 mg/kg (dry weight basis) for Pb, Cd, Hg, Cu, Mn, Zn, Fe, Co, As, Ca, Na, K, Mg, Ba, Ni, Ti, Cr, Al, Bi, Sb, and Ag in Russula foetens, Agaricus bisporus, Hypholoma fasciculare, Hydnum repandum, Lactarius sp., Tricholoma terreum, Amanita vaginata, Laccaria lacceta, Pleurotus ostreatus, Hypholoma fasciculare, Pleurotus ostreatus, Hypholoma fasciculare, Agaricus bisporus, Pleurotus ostreatus, Lactarius piperatus, Hydnum repandum, Russula sp., Agaricus bisporus, Russula delica, and Lactarius sp., respectively.     

基于无机多元素分析鉴别我国主要进口大米产地

目的利用大米中无机多元素分析数据建立判别模型,实现对4个我国进口大米主要产地的鉴别。方法采用ICP-MS和ICP-OES分析技术,测定了泰国、巴基斯坦、柬埔寨、缅甸4个产地的76份大米样本中磷、钾、镁、钙、锌、钠、锰、铁、铷、铜、硼、铝、钼、镍、钡、锶、砷、钛、硒、铬、钴、铯、铅、镉、锂、钒、银、锑、铍、铊、镧、铈、镨、钕、钐、铕、钆、铽、镝、钬、铒、铥、镱、镥、钪、钇等46种无机元素含量。通过对检测数据进行单因素方差分析、Fisher判别分析,建立了产地判别模型。结果4个产地大米的部分元素存在显著性差异,产地判别模型的原始校验准确率100%,交叉验证准确率96.1%。结论所建方法和判别模型对泰国、巴基斯坦、柬埔寨、缅甸所产大米具有很好产地鉴别能力。     

中宁枸杞中矿物元素在生长期的动态变化研究

利用电感耦合等离子体质谱对宁夏中宁枸杞中55种矿物元素在不同成熟阶段的含量进行跟踪测定,分析其变化规律.结果表明,中宁枸杞中55种元素含量差异较大,Cu、Co、B、Mg、Mn、Mo、Ca、Cd、Cr、Ni、Ba、Sr、Rb、Ti、W、Ga元素含量在5个成熟阶段呈降低趋势,Fe、Zn、V、Pb、As、Hg、Sb、Tl、L...     

不同蔬菜对保加利亚乳杆菌生长的影响

为了说明发酵蔬菜制品中的浆水菜在发酵过程中发酵菌对原料蔬菜的选择性,以保加利亚乳杆菌(Lactobacillus bulgaricus)为菌种,以48种常见蔬菜为原料,按照浆水菜制作工艺,实验研究了菌体在添加不同蔬菜中的生长的情况。结果表明,添加白萝卜、黄瓜、山药、番茄、胡萝卜、小白菜、小青菜、油麦菜、芹菜、冬瓜等蔬菜的,保加利亚乳杆菌生长的很好,菌体浓度均可达到108cfu/mL以上;添加土豆、菠菜、海带、黄豆芽、油菜、芥菜、苦菊、芥蓝、茴香、菜花、莴笋、茄子、南瓜、西葫芦、苜蓿等蔬菜的,保加利亚乳杆菌有生长,菌体浓度在107cfu/mL左右;添加平菇、空心菜、生菜、大葱、蒜苔、青椒、大白菜、西兰花、茼蒿、韭菜、香椿、地瓜、紫薯、莲藕、娃娃菜、荷兰豆、苦瓜、紫甘蓝、丝瓜、冬笋、豇豆、香菜、洋葱等蔬菜的保加利亚乳杆菌没有生长。      

Measurement of energy cost of selected household and farm activities performed by rural women

A nutritional study was carried out on 30 rural, low-income women, aged 25 to 35 years, in the village of Dhandra, Ludhiana District, Punjab, India, to measure the energy cost of selected household and farm activities. The mean weight, mid-upper-arm circumference, and triceps skinfold thickness were below the reference standards. A negative energy balance among the subjects indicated their poor energy status. The energy costs of selected household and farm activities were assessed by the Caltrac personal activity computer. The energy costs of household activities--making dough, making chapatis, grinding masala, hand pumping, washing utensils, sweeping, mopping, washing the floor, mud pasting, and washing clothes--were 0.0306, 0.0281, 0.0595, 0.0337, 0.0266, 0.0424, 0.0530, 0.0331, 0.0634, and 0.0453 kcal/kg/min, respectively. The energy costs of farm activities--collecting fodder, chaffing fodder, milking, making dung cakes, picking sag, harvesting wheat, bundling wheat, picking paddy, brooming paddy, and separating paddy--were 0.0472, 0.0372, 0.0530, 0.0270, 0.0337, 0.0623, 0.0374, 0.0411, 0.0370, and 0.0744 kcal/kg/min, respectively. All selected activities were categorized as light, except for grinding masala, mopping, mud pasting, harvesting wheat, separating paddy, and milking, which were categorized as moderate on the basis of Food and Agriculture Organization (FAO) physical activity ratios. The Caltrac gave lower values for the energy costs of most of the activities. Although it is simpler and less costly, the Caltrec must be calibrated against methods of measuring oxygen consumption for similar activities.     

Constituents of the essential oil of Sideritis cretica boiss

The essential oil constituents of Sideritis cretica Boiss have been investigated by gas chromatography-mass spectrometry. Over 30 compounds were identified or partially identified in the oil which was obtained by steam distillation. The compounds reported in this work are: limonene, β-phellandrene, γ-terpinene, p-cymene, hexanol, nonanal, 1-octen-3-ol, a-copaene, linalool, octanol, 1-terpinen-4-ol, caryophyllene, pulegone, β-farnesene, terpineole, borneol, carvone, naphthalene, zingiberene, trimethyl-dihydro-naphthalene, β-cadinene, ar-curcumene, anethol, damascenone, calamene, colacorene, hexenyl benzoate, γ-decalactone, drimenol, thymol, carvacrol, diterpenes, diethyl phthalate and benzyl benzoate.     

Elemental fingerprint of wines from the protected designation of origin Valencia

Inductively coupled plasma optical emission (ICP-OES), in combination with different chemometric approaches, has been used to verify the origin of different red wine samples from Utiel-Requena, Jumilla, Yecla and Valencia protected designation of origin (PDO). The ability of multivariate analysis methods, such as hierarchical cluster analysis (HCA), principal component analysis (PCA), classification and regression trees (CARTs) and discriminant analysis (DA), to achieve wine classification from their elemental contents has been investigated. The calculations were performed using 38 variables (contents of Al, Ba, Be, Ca, Cd, Ce, Co, Cr, Cu, Dy, Er, Eu, Fe, Gd, Ho, K, La, Li, Lu, Mg, Mn, Mo, Na, Nd, Ni, Pb, Pr, Sc, Se, Sm, Sr, Tb, Ti, Tm, V, Y, Yb and Zn, at mg l⁻¹ level, determined by ICP-OES).     

中国烟叶矿质营养及主要化学成分含量特征研究

利用2002年抽样调查的220个烤烟样品,对我国烤烟中的氮、钾、磷、钙、镁、锰、铜、锌、硼、钠、铁、氯、烟碱、还原糖等14个指标的含量特征进行了分析。结果表明:1)除钙、钠、锌、硼、还原糖、烟碱外,其余指标在品种之间的差异极显著,但不同指标在品种之间的高低秩序不同。在样本数较多的K326、云烟85、云烟87、NC82、NC89中,K326的钾含量为1.79%,显著地高于云烟85、NC82、NC89,NC82、云烟87的氯含量分别为0.39%、0.32%,显著地高于K326、云烟85、NC89中的氯含量;2)氮、硼、烟碱含量从上部烟叶到下部烟叶显著地依次降低,而钾、铁、还原糖则从上部烟叶到下部烟叶显著地依次升高;3)烟碱含量地域之间的差异不明显,而其余指标在地域之间的差异极显著,但不同指标在品种之间的高低秩序不同。河南烟叶的钾含量显著地低于其他省份,贵州烟叶的氯离子含量显著地高于其他地方,湖南烟叶的还原糖含量显著地低于其他所有地方;4)我国烟叶氮、磷、钾、钙、镁、锰、氯、铜、锌、硼、钠、铁、烟碱、还原糖含量落在巴西烟叶范围之内的理论概率分别为0.525、0.598、0.485、0.338、0.462、0.839、0.449、0.384、0.275、0.586、0.621、0.586、0.739、0.684;还原糖、烟碱、钾、氯含量符合"国际型优质烟叶"质量标准的概      

Physicochemical Properties,Minerals, Trace Elements,and Heavy Metals in Honey of Different Origins: A Comprehensive Review

Honey is a popular natural food product with a very complex composition mainly consisting of both organic and inorganic constituents. The composition of honey is strongly influenced by both natural and anthropogenic factors, which vary based on its botanical and geographical origins. Although minerals and heavy metals are minor constituents of honey, they play vital role in determining its quality. There are several different analytical methods used to determine the chemical elements in honey. These methods are typically based on spectroscopy or spectrometry techniques (including atomic absorption spectrometry, atomic emission spectrometry, inductively coupled plasma mass spectrometry, and inductively coupled plasma optical emission spectrometry). This review compiles available scientific information on minerals and heavy metals in honey reported from all over the world. To date, 54 chemical elements in various types of honey have been identified and can be divided into 3 groups: major or macroelements (Na, K, Ca, Mg, P, S, Cl), minor or trace elements (Al, Cu, Pb, Zn, Mn, Cd, Tl, Co, Ni, Rb, Ba, Be, Bi, U, V, Fe, Pt, Pd, Te, Hf, Mo, Sn, Sb, La, I, Sm, Tb, Dy, Sd, Th, Pr, Nd, Tm, Yb, Lu, Gd, Ho, Er, Ce, Cr, As, B, Br, Cd, Hg, Se, Sr), and heavy metals (trace elements that have a specific gravity at least 5 times higher than that of water and inorganic sources). Chemical elements in honey samples throughout the world vary in terms of concentrations and are also influenced by environmental pollution.     

Characterization of traditional and exotic apple varieties from Portugal. Part 1 – Nutritional,phytochemical and sensory evaluation

Phytochemical and nutritional characterization of traditional (Bravo de Esmolfe, Malápio Fino, Malápio da Serra, and Pêro Pipo) and exotic (Golden, Starking, Fuji, Reineta Parda and Gala Galaxy) apple varieties from Portugal were performed. Measurements were taken on 43 parameters including water, protein, sugars, acids, fibre, vitamins (C, A,B1, B2, B3, B5, B6, B9, β-carotene and α-tocopherol), minerals (K, P, Mg, Ca, S, Na, Si, B, Fe, Al, Cu, Mn, Zn, Ni, Mo, Cd) and polyphenols (total, catechin, epicatechin, chlorogenic acid, phloridzin, quercetin-3-glucoside, quercetin-3-rhamnoside, kaempferol-3-glucoside, procyanidins B1 and B2). Nutritional composition results showed that traditional apples had higher contents of fibre, protein, sugars, β-carotene, vitamin E, Mg and phenolic compounds. A comparison between unpeeled and peeled apples was also performed for the Bravo de Esmolfe variety and the unpeeled apples had higher amounts of fibre. Results from sensory evaluation of traditional apples performed by selected assessors and consumers showed there were differences among sample attributes such as sourness, juiciness and hardness, and two apple varieties were preferred (Bravo de Esmolfe and Pêro Pipo) for their odour, taste, hardness and juiciness.