Influence of seed roasting process on the changes in composition and quality of sesame (Sesame indicum) oil

The composition and quality changes of sesame oils prepared at different roasting temperatures (180–260°C) from sesame seed were evaluated and compared with an unroasted oil sample. There were no apparent differences in characteristics, such as acid value, iodine value, saponification value and refractive index, of sesame oils prepared at a roasting temperature between 180 and 220°C. The colour units and total polar content of oils increased in relation to an increase in roasting temperature. The phospholipid content was reduced from 690 mg kg^?1 in unroasted oil to 0 mg kg^?1 in the oil prepared using a 260°C roasting temperature. The fatty acid content of the oil was reduced markedly, especially in oleic and linoleic acids, when the roasting temperature was over 220°C. The amounts of chlorophyll and sesamolin decreased with increasing roasting temperature. However, the highest level of sesamol and γ-tocopherol was found in oils prepared with a 200–220°C roasting temperature. The sesame oil prepared at a 200°C roasting temperature had the best flavour score when compared with the other samples.     

焙炒条件对芝麻油中多环芳烃含量的影响

对芝麻进行不同条件焙炒实验,榨取芝麻油,之后对不同焙炒条件下芝麻油中多环芳烃含量进行检测分析。结果表明:随着焙炒时间的延长、焙炒温度的升高,芝麻油中B[a]P、PAH4、PAH16的含量都呈现明显上升趋势;对照国标GB 2716—2005及欧盟No835/2011号法规关于B[a]P和PAH4的限量,芝麻籽的合理焙炒时间不宜超过30 min,焙炒温度不宜超过200℃;焙炒时间为30 min的条件下,焙炒温度在200~240℃之间时,有利于3环物的积累,而焙炒温度达到260℃时,则有利于4环物及重质多环芳烃的积累。     

秘鲁鱿鱼烤制过程中的品质变化

烤制作为鱿鱼丝加工中的关键工序,对鱿鱼的品质有重要的影响。本文主要研究了秘鲁鱿鱼在烤制过程中色泽、营养成分、安全性及风味的变化。结果表明,随着烤制时间的延长,秘鲁鱿鱼色泽加深;氨基酸含量下降,其中谷氨酸、天冬氨酸和亮氨酸含量下降最明显,而人体必需氨基酸含量降幅不大;牛磺酸的含量略有降低;甲醛含量随着烤制时间的延长而升高;香气物质的种类显著增加,其中吡嗪、噻唑等杂环化合物对烤香风味的形成具有重要作用。      

Effects of roasting conditions of sesame seeds on the oxidative stability of pressed oil during thermal oxidation

Oxidative stability of sesame oil (SO) prepared from sesame seeds roasted at 213, 230, and 247 °C for each 14, 21, or 28 min was determined at 180 °C heating condition by 2,2-diphenyl-1-picrylhydrazyl (DPPH), conjugated dienoic acid (CDA) value, headspace oxygen analysis, and profile changes of sesamol and sesamolin. As sesame seeds were roasted with longer time and higher temperature, more sesamol was found in SO. SO from sesame seeds roasted at 247 °C for 28 min had the highest oxidative stability based on the results of CDA and headspace oxygen. Absorbance of DPPH from SO roasted at 230 and 247 °C showed different patterns compared to those from SO at 213 °C during thermal oxidation. Sesamol was continuously generated with the decrease of sesamolin in SO from 230 to 247 °C while sesamol in SO from 213 °C did not increase during 180 °C heating. Higher oxidative stability of SO may be related with the continuous generation of sesamol from the degradation of sesamolin during thermal oxidation rather than the initial antioxidant content.     

Comparison of fatty acid profile changes between unroasted and roasted brown sesame (Sesamum indicum L.) seeds oil

The conditions of roasting are the key step in manufacturing Sesame (Sesamum indicum L.) oil. Roasting sesame seeds changed its oil, moisture, and ash content. In oils from unroasted and roasted seeds, nine fatty acids analyzed by gas chromatography-mass spectrometry. The fatty acids composition were changed in both oils. Oleic and linoleic changed in large amount, but changes for other fatty acids were small. ¹H and ¹³C NMR analysis showed the frequency changes for both oils, the roasting condition caused to shift the frequency to lower degree.     

不同品种核桃仁成分及烘烤对其油脂品质 和内源性蛋白酶活性的影响

旨在为工业去衣核桃仁的烘烤处理条件提供参考,选择我国4个品种核桃仁作为研究对象,比较了4种核桃仁的蛋白质和脂肪含量,分析了其氨基酸和脂肪酸组成,并考察了烘烤（60~140 ℃烘烤1~3 h使水分含量降至5%以下）对这4种去衣核桃仁油脂品质及内源性蛋白酶活性的影响。结果表明：核桃仁蛋白质（13.73%~17.54%）、脂肪（69.10%~72.77%）含量及其油脂亚麻酸含量（8.77%~13.23%）在品种间存在显著性差异（p<0.05）,而氨基酸组成未表现出明显差异;随着烘烤温度的升高,4种去衣核桃仁油脂的酸值及过氧化值均呈现不断上升的趋势,但均未超过国家标准要求;未烘烤核桃仁内源性蛋白酶活性在品种间也存在显著性差异（p<005）;烘烤温度对核桃仁内源性蛋白酶活性有显著影响,60~80 ℃烘烤尚且保留了大部分的内源性蛋白酶活性,而100~140 ℃烘烤核桃仁内源性蛋白酶活性大幅度下降甚至丧失。综上,烘烤对去衣核桃仁油脂及内源性蛋白酶的影响并不因核桃品种的不同而产生差异,60~80 ℃的烘烤适合生产高内源性蛋白酶活性的去衣核桃仁（坚果类产品）。     

The contents of lignans in commercial sesame oils of Taiwan and their changes during heating

Sesame lignans have multiple functions and were recently reported to have potential as sources of phytoestrogens. Sesame oils used in Taiwan are expelled from roasted sesame seeds with dark colour and strong flavour. This study analyzed lignan contents of 14 brands of sesame oils, and found their mean of total lignans to be 11.5 mg/g; 82% and 15% of the lignans were sesamin, and sesamolin, respectively. Sesamol contents were relatively higher in those with darker colour. In use as a cooking oil, heating at 180 °C for 4 min did not change the content of lignans, but the level of sesamol increased after heating at 180 °C for 20 min. Heating at 200 °C for 20 min caused a significant loss of sesamolin and sesamol. From our calculation, ingestion of 10 g of sesame oil is adequate to provide the level of lignans that might benefit cardiovascular health, as found by other studies. Cooking at temperatures above 200 °C will cause loss of some lignans, but sesamin, a source of phytoestrogen, is relatively heat-stable.     

焙炒时间对芝麻油风味及芝麻氨基酸含量的影响

本文主要研究焙炒时间对芝麻油挥发性风味成分及芝麻中氨基酸含量(以芝麻脱脂粕中氨基酸含量为依据)的影响。经过不同时间焙炒的芝麻,用水代法提油,然后采用顶空固相微萃取(HS-SPME)结合GC/MS技术,检测芝麻油中的挥发性风味成分。随着焙炒时间的延长,吡嗪类、吡咯类、吡啶和嘧啶类、含硫类、呋喃类、酚类物质的相对含量逐渐增多,醛类、醇类、烃类和环氧烃类等物质的含量逐渐减少。对芝麻脱脂粕中18种氨基酸含量的检测数据显示,随着焙炒程度加深,氨基酸含量呈总体下降趋势,其中精氨酸、丝氨酸、赖氨酸和胱氨酸的含量减少明显,这4种氨基酸对芝麻油香味的形成可能起到了重要的作用。     

大枣浓缩汁贮藏过程中非酶褐变动力学研究

在4,26,37℃条件下对大枣浓缩汁进行7个月的贮藏,并分别用零级、一级动力学模型对产品中与非酶褐变相关的指标还原糖、抗坏血酸(Vc)、羟甲基糠醛(HMF)随贮藏时间的变化进行拟合分析。结果表明:还原糖含量的动态变化零级模型拟合度优于一级的,Vc含量的动态变化一级模型拟合度优于零级的。4,26,37℃贮藏条件下,大枣浓缩汁中的HMF和A420变化呈线性关系,同时颜色参数(A420、L*、Chroma值)是HMF的函数,具有相关性,可用一级动力学方程表示。26,37℃贮藏过程中大枣浓缩汁的颜色参数及还原糖、Vc含量变化显著(P0.05),明显高于4℃贮藏,低温有利于大枣浓缩汁的贮藏。     

青梅烟熏过程中的色泽变化

本文研究了烟熏处理对青梅非酶褐变的影响,以新鲜青梅为研究对象,分析了青梅在烟熏过程中褐变指数、色泽、还原糖、总糖、氨基酸以及5-羟甲基糠醛（5-HMF）的变化情况。结果表明,随着烟熏时间的延长,褐变度、色差值和5-HMF的含量逐渐增加,还原糖、总糖和氨基酸含量逐渐减少。     

Study of acrylamide in coffee using an improved liquid chromatography mass spectrometry method: Investigation of colour changes and acrylamide formation in coffee during roasting

An improved analytical method for the determination of acrylamide in coffee is described using liquid chromatography coupled to mass spectrometric detection (LC-MS). A variety of instant, ground and laboratory roasted coffee samples were analysed using this method. The sample preparation entails extraction of acrylamide with methanol, purification with Carrez I and II solutions, evaporation and solvent change to water, and clean-up with an Oasis HLB solid-phase extraction (SPE) cartridge. The chromatographic conditions allowed separation of acrylamide and the remaining matrix co-extractives with accurate and precise quantification of acrylamide during MS detection in SIM mode. Recoveries for the spiking levels of 50, 100, 250 and 500 µg/kg ranged between 99 and 100% with relative standard deviations of less than 2%. The effects of roasting on the formation of acrylamide and colour development were also investigated at 150, 200 and 225°C. Change in the CIE (Commission Internationale de l'Eclairage) a* colour value was found to show a good correlation with the change in acrylamide. CIE a* and acrylamide data was fitted to a non-linear logarithmic function for the estimation of acrylamide level in coffee. Measured acrylamide levels in commercial roasted coffees compared well with the predicted acrylamide levels from the CIE a* values.     

Changes in polyphenol ability to produce astringency during roasting of cocoa liquor

Polyphenols in cocoa products determine the astringent sensation due to their interaction with salivary proline‐rich protein. Changes in the ability of polyphenols to produce astringency during cocoa roasting have been studied through an evaluation of the polyphenol–protein interaction in cocoa cake/liquor roasted at 120 °C for 45 min, with and without enrichment with polyphenol extract. Roasting decreased the capacity of polyphenols to interact with protein, causing a decrease in astringency. However, the polyphenol–protein interaction products after roasting could still be oxidized enzymatically and most probably would still give cocoa products beneficial effects as functional food. Copyright © 2005 Society of Chemical Industry     

Comparison of litchi polysaccharides extracted by four methods: composition,structure and in vitro antioxidant activity

Water-soluble polysaccharides (LCPs) were extracted from litchi, wherein LPS, LPH, LPP and LPM were extracted by ultrasound, hot water, ultra-high pressure and microwave methods, respectively. The physicochemical properties, components, structures and in vitro antioxidant activities of four LCPs were investigated. LPP was the highest in yield and purity, and most physicochemical properties of four LCPs were similar. FTIR showed that LPP, LPS and LPH had ɑ-dominating configuration in pyranose rings. SEM showed that four LCPs were different, and LPH and LPP had relatively smooth and compact surfaces. The Mw of LPS, LPH, LPP and LPM were 79 538, 320 213, 192 891 and 200 198 Da, respectively. All four LCPs consisted of fucose, galactose, glucose and rhamnose. Except for LPS, the other three LCPs contained mannose. Based on the results of in vitro antioxidant activity, 5 mg mL⁻¹ LPP presented the highest in DPPH and hydroxyl scavenging activity, while it ranked secondly in reducing power.     

热破碎番茄浆贮藏期间非酶褐变动力学分析

探讨热破碎番茄浆在贮藏过程中非酶褐变的规律,以期为番茄浆的贮藏提供指导。在0、25℃和37 ℃条件对其进行了5个月的贮藏研究,并对产品中与非酶褐变相关的指标总氨基酸、总糖、维生素C(VC)、5-羟甲基糠醛(HMF)和褐变度(BD)的变化分别应用零级、一级、联合动力学模型进行了拟合分析。结果表明：联合动力学模型较零级、一级动力学模型能更好地解释热破碎番茄浆贮藏过程中非酶褐变的动态变化。25℃和37 ℃贮藏过程中,热破碎番茄浆中HMF含量和BD的变化呈线性关系,同时颜色指标亮度L*、红值a*、黄值b*是HMF的函数,可用联合动力学方程表示。较高的贮藏温度(25℃和37℃)对热破番茄浆中总氨基酸、总糖、VC、HMF含量、BD以及颜色指标(亮度L*、红值a*、黄值b*)影响显著(P＜0.05),较低温度(0℃)贮藏条件下,HMF含量、褐变度BD及颜色指标变化不明显(P＞0.05)。表明高温贮藏显著降低热破碎番茄浆的品质,而低温贮藏可有效保护热破碎番茄浆的品质。     

草莓脯贮藏期间非酶褐变的化学途径分析

为确定贮藏期间草莓脯褐变的化学途径,将草莓脯分别于37、25、4 ℃条件下贮藏,测定其色泽以及抗坏血酸、总酚、3 种游离糖、5 种游离氨基酸和5-羟甲基糠醛（5-hydroxymethylfurfural,5-HMF）含量,并进行相关性和聚类分析。结果表明：随着贮藏时间延长,3 个温度下 草莓脯L*、a*、b*值均呈下降趋势,贮藏90 d色差ΔE为11.42～33.33,说明草莓脯贮藏期间色泽发生明显变化;抗坏血酸、总酚、游离糖和氨基酸含量出现不同程度的下降;5-HMF含量则呈线性上升;相关性分析结果显示除谷氨酰胺含量外,其他色泽及化学指标与ΔE呈显著、极显著或高度显著相关（P＜0.05、P＜0.01、P＜0.001）,说明色泽变化可能是抗坏血酸降解、多酚氧化和美拉德反应等途径的共同作用结果;聚类分析则将样品分为两类,较高温度、较长时间贮藏的样品与其他样品能够得以区分,说明温度与时间对褐变程度的影响不可忽略。总之,在草莓脯贮藏期间的褐变过程中,同时存在抗坏血酸、酚类、糖和氨基酸参与的褐变反应,但各成分含量变化与褐变程度存在不同步性。本实验结果可为草莓脯贮藏期间的褐变控制提供借鉴。     

核桃仁发育过程中不同形态酚及其抗氧化活性的动态变化

阐明发育期核桃仁中3种不同形态酚（游离、酯化和结合）及其单体酚组成的变化,探究酚类成分与抗氧化能力的关系,为深入了解核桃功能性成分形成规律和深化功能性产品开发提供参考。以核桃品种‘寒丰’为对象,运用UPLC-MS/MS测定3种形态酚组成,分光光度计法测定核桃的羟自由基清除能力,皮尔逊相关分析用于研究酚类物质与羟自由基清除能力的相关性关系。在核桃仁发育过程中,酚形态中以游离态为主且占比大于58%;3种形态总酚含量最高值均出现在采前63 d,分别为10.47 mg/g（游离态）、2.76 mg/g（酯化态）、1.28 mg/g（结合态）;鞣花酸、咖啡酸、绿原酸等单体酚的3种形态含量随着核桃仁发育显著降低58.03%-88.83%;单体酚含量与抗氧化活性呈现显著相关性,相关系数为0.63-0.97。核桃仁3种形态总酚含量和抗氧化活性最大值均出现在未成熟早期,游离态是核桃仁中提供抗氧化活性的酚类物质主要形态,并且核桃仁发育过程中单体酚的抗氧化能力与成熟度、酚形态有关。这些发现将对核桃的适时采摘和营养管理以及核桃仁深度开发利用、产业提质增效等提供重要的基础数据和理论参考。     

Structural and chemical changes in cocoa (Theobroma cacao L) during fermentation,drying and roasting

Cocoa seeds and pulp were fermented for 144 h, followed by natural drying. The tegument was removed and the cotyledons were broken into nibs which were roasted at 150 °C for 30 min. Non‐fermented material, material fermented for 24, 48 and 72 h, material fermented for 144 h and then dried, and also the roasted nibs, were all prepared for chemical and microscopic analyses. Light microscopy revealed the presence of anionic and cationic residues and of neutral sugars. During fermentation there was a reduction in the cytoplasmic content of phenolic compounds and in the number of protein bodies. The cell wall showed a reduction in anionic residues and a loss of crystallinity. These alterations were maximum after 72 h. Drying and roasting increased the number of damaged cells and reduced the amount of cytoplasmic material. The chemical analyses generally confirmed the microscopy results. The concentration of amino‐terminal groups and total free amino acids increased during fermentation (up to 72 h), but returned to the initial values after roasting. The principal chemical changes were related to reducing sugars, free amino acids, proteins and phenols, and PCA was suggested as a useful tool to compare different samples. Microscopic analysis revealed the degradation of protein and phenolic bodies and cellular damage during roasting. © 2000 Society of Chemical Industry