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1.
BACKGROUND: Pistacia vera ‘Kerman’ is the predominant pistachio nut cultivar in the United States (California), the world's second largest producer. Despite several reports on the essential oil (EO) content in the genus Pistacia, data on ‘Kerman’ are limited. The EO content and volatile organic compound (VOC) emissions of tree nut orchards are of current interest to researchers investigating insect pests and the potential role of EO and VOCs as semiochemicals. To establish a basis for the VOC output of pistachios, the EO content of fruits, peduncles, and leaves was analyzed. RESULTS: Evaluated plant parts contained limonene as the primary EO component, followed by α‐terpinolene. Peduncles were unique in containing relatively high levels of α‐thujene. The results were reproducible between two different geographical locations. In situ solid phase microextraction (SPME) studies demonstrated the volatile emission was representative of the EO composition. CONCLUSION: This is the first report detailing the content and distribution of EO and the unique limonene‐dominant profile for this Pistacia vera cultivar which may influence pistachio insect pest semiochemical research. Copyright © 2010 Society of Chemical Industry  相似文献   

2.
对不同生长期的重庆1号、重庆2号品种的毛叶山桐子果实的整果、果肉和种子中的基本化学成分含量进行比较,并运用气相色谱法对油脂中脂肪酸组成及相对含量进行分析.结果表明,2个品种果实在不同生长期和不同部位中粗脂肪、蛋白质、总糖、灰分、总酚、总黄酮等成分含量差异显著(P<0.05);2个品种毛叶山桐子作为油脂原料的最佳采收期分...  相似文献   

3.
Olive fruit of cv ‘Mastoides’ grown on two locations at altitudes of 100 and 800 m were harvested at three dates and used for determination of average weight, fruit oil and moisture contents and the following oil quality characteristics: titratable acidity, peroxide value, K232,270 coefficients, total phenol, tocopherol and chlorophyll content as well as fatty acid and phenol composition. Towards maturation, fruit moisture content decreased but oil content increased. Titratable acidity of oil of both altitudes was low, with higher the oil obtained from fruits from 100 m. Oil peroxide value was higher in the oil of fruits from 800 m at all harvest times and it showed an increase towards maturation in both locations. Total phenol content was higher in oil from 100 m elevation and showed a gradual decrease towards maturation at both altitudes. The ratio unsaturated saturated fatty acids was higher in oil of fruits from 800 m at the first two harvest dates but did not differ significantly at the third harvest. Only α-tocopherol was found in the oil from both elevations. Some phenolic compounds were detected in the first harvest but disappeared with fruit maturation, while other compounds not detected in the first harvest appeared later. Elevation influenced not only the phenol content but also its composition.  相似文献   

4.
ABSTRACT: Eight almond (Prunus dulcis L.) cultivars from 12 different California counties, collected during crop years 2004 to 2005 and 2005 to 2006, were extracted with petroleum ether. The extracts were subjected to GC‐MS analyses to determine fatty acid composition of soluble lipids. Results indicated palmitic (C16:0), oleic (C18:1), linoleic (C18:2), and α‐linolenic (C18:3) acid, respectively, accounted for 5.07% to 6.78%, 57.54% to 73.94%, 19.32% to 35.18%, and 0.04% to 0.10%; of the total lipids. Oleic and linoleic acid were inversely correlated (r=–0.99, P= 0.05) and together accounted for 91.16% to 94.29% of the total soluble lipids. Statistically, fatty acid composition was significantly affected by cultivar and county.  相似文献   

5.
When the Fahrenheit temperature scale is superseded a replacement will be required for the present “Gravity Lost” Table. A mechanism is suggested whereby such a Table for 20° C may be validly calculated from the existing 60° F Table.  相似文献   

6.
The influences of dietary supplementation with α‐tocopheryl acetate (α‐TA) and of processing (by hard‐boiling and scrambling) of eggs enriched with ω3 fatty acids, either very long‐chain ω3 polyunsaturated fatty acids (VLC ω3 PUFAs) or linolenic acid (LNA), on fatty acid composition, α‐tocopherol content and lipid oxidation (thiobarbituric acid (TBA) values) were studied. Four dietary treatments were formulated from a basal diet containing 40 g kg?1 linseed oil (LO) or fish oil (FO) combined with either 0 or 100 mg α‐TA kg?1 of feed. Eggs from LO treatments were enriched with LNA and those from FO treatments were rich in VLC ω3 PUFAs. Neither processing nor dietary supplementation with α‐TA modified greatly the fatty acid profile of eggs. Dietary supplementation with α‐TA increased the α‐tocopherol content of eggs (187.2 versus 407.9 µg g?1 dry matter). Eggs from FO treatments showed lower α‐tocopherol content than those from LO treatments (273.5 versus 321.6 µg g?1 dry matter), and processing of eggs enriched with VLC ω3 PUFA reduced the α‐tocopherol content by a significant 16%. Moreover, processing of eggs increased lipid oxidation two‐ to nine‐fold. Oxidation levels of hard‐boiled eggs were 30.4% higher than those of scrambled eggs. TBA values in hard‐boiled and scrambled eggs were significantly reduced when 100 mg α‐TA kg?1 of feed supplemented the diet only in those eggs enriched with VLC ω3 PUFA (from FO treatments). Copyright © 2003 Society of Chemical Industry  相似文献   

7.
Hazelnuts (Corylus avellana L.) were collected from three different cultivars (Tombul, Palaz and Kal?nkara) at the harvest season of 1996. The dried nuts were stored shelled and unshelled in polyethylene bags at 21C and 60–65% relative humidity for 12 months. During storage, the total fat content increased, the palmitic and oleic acid content of the oil increased, linoleic acid, ranged from 12.41 to 10.35%. No significant differences were found for other fatty acids during storage. The effect of storage of shelled and unshelled hazelnuts on the total fat content was significant.  相似文献   

8.
研究了晶甜5号和晶甜紫花糯2号两种鲜食玉米在早于适采期、适采期和晚于适采期三个采收期脂氧合酶(LOX)的活力、脂肪酸和挥发性成分的组成及变化情况。结果显示样品的LOX活力为2.63~4.28 U/g FW,脂肪酸均以亚油酸的含量最高(32.40%~46.68%),而亚麻酸含量较低(0.97%~2.40%)。挥发性成分则以己醇或己醛的含量最高,早采和适采期的晶甜5号中己醇含量最高,晚采的晶甜5号和三个采收期的京甜紫花糯2号均以己醛含量最高。两种玉米的粗脂肪、脂氧合酶活力随采收期的延后而增加,但是亚油酸、己醛却表现为下降趋势。相关性分析表明LOX途径的底物脂肪酸亚油酸和亚麻酸与己醛呈现显著正相关关系,但与LOX活力的相关性未达显著水平。这说明鲜食玉米中来自LOX途径的挥发性成分可能主要取决于亚油酸或亚麻酸的量,而并非LOX活力的大小。另外,两种玉米挥发性成分尤其是C6醛醇含量的不同可能体现了样品间LOX途径上的差异。  相似文献   

9.
10.
A preliminary study of malting conditions for six Thai rice cultivars was conducted. Three non‐glutinous rice cultivars (KDML105, PT60, and WR) and three glutinous rice cultivars (SPT, RD6, and KND) were selected. The steeping durations (24, 48, and 72 h) and temperatures (20, 25 and 30°C) were investigated for their effect on α‐ and β‐amylase, the key enzymes for malt quality evaluation. During steeping, the production of both enzymes was lower than at the germination process. The longer the steeping duration, the lower the maximum β‐amylase activity obtained. The contradictory effect was observed for α‐amylase activity, near the end of the germination time. Additionally, temperature influenced the water absorption content as well as the amylolytic enzyme activity. Particularly at 30°C, the maximum β‐amylase activity (6.7 unit/mg protein) was found in KND malt steeped for 24 h, and maximum α‐amylase activity (20 unit/mg protein) was found in PT60 malt steeped for 72 h. The amount of enzyme production depended on the variety rather than the amylose content in the rice. The optimal condition for malting rice regarding β‐amylase activity and α‐amylase activity was analyzed at 30°C, with steeping for 24 h and germination for 4–5 days.  相似文献   

11.
Four mixtures of ground barley and soya bean meal were prepared; the first had no further additive, the second had 10% soya bean oil, the third 0.05% chromic oxide and the fourth both 10% soya bean oil and 0.05% chromic oxide. Each of these mixtures was then dried in three ways: at 30°C in vacuo and at 60 and 100°C in a forceddraught oven. The total fatty acid content and the fatty acid composition of each sample was determined either by direct esterification of the fatty acids with methanolsulphuric acid or by extraction into chloroform-methanol followed by esterification with sodium methoxide. When the mixture containing both oil and chromic oxide was heated at 100°C, about 25% of the polyunsaturated fatty acids were lost when they were directly esterified and about 50% when the fat was first extracted from the mixture. It is concluded that this loss is probably due to oxidation of the polyunsaturated fatty acids by the chromic oxide and that the additional loss observed when the extraction method was used is due to partial insolubilisation of the triglyceride by these oxidised fatty acids.  相似文献   

12.
从河南省林木品种审定委员会认定的适宜在本地区推广的长林系列品种中选出具有代表性的主栽油茶品种长林18号、40号、53号和配栽油茶品种长林166号,采用气相色谱-质谱法(GC-MS)对4个油茶品种茶籽仁中脂肪酸组成和含量进行分析,检验了其干籽出仁率和脂肪含量,并对脂肪含量及脂肪酸组分进行了相关性分析。结果表明:3个主栽品种与1个配栽品种干籽出仁率的差异达到了显著水平(p0.05),但不同品种茶籽脂肪含量差异不大;共检测到了17种脂肪酸组分,其中,茶籽仁中常量组分顺-油酸的含量26.25%~30.82%、棕榈酸的含量2.86%~3.22%、亚油酸的含量3.25%~3.86%。长林40号茶籽中饱和脂肪酸、单不饱和脂肪酸、多不饱和脂肪酸比值为1:6.08:1.05,最接近国际营养学家提出油脂中三类脂肪酸的最佳供能比1:6:1。相关性分析显示,脂肪含量与棕榈酸有一定的相关性,相关系数达到了0.64。结合河南省林木品种审定委员会的研究结论可得,长林40号油茶良种不仅产量高、抗性强,而且干籽出仁率高、含油量高,茶籽脂肪酸组成合理,综合性状优于其他三个品种。  相似文献   

13.
The chemical profile, mineral content as well as antioxidant activities of three cultivars of Pistacia vera cv Kerman were investigated. The total phenolic (TP) content flavonoids (FT) and anthocyanins (TA) were measured. Additionally, the profile of polyphenols was analyzed. A slight, not significant, increment was observed in TP content between cultivars with different age (5, 9 and 11 years old). The 9 years old cultivar showed the highest FL value, while the 11 years old cultivar had the higher TA content. Main polyphenols were separated by HPLC and identified by electrospray ionization (ESI) coupled to quadrupole-time of flight mass spectrometry (LC–ESI–QTOF–MS). Gallic acid and (+)-catechin were present in higher amounts. The presence of myricetin, isoquercitrin and a dimer of procyanidin are reported for the first time in pistachio. Additionally, K, Ca and Mg were found in high proportion. The highest antioxidant capacity was measured in the 11 years old pistachio cultivar. This work presents the first evidence that Pistacia vera cv Kerman from Argentinean cultivars could be considered as a functional food or ingredient in a diet, with potential to improve human health.  相似文献   

14.
The effects of harvest date and cold storage period on ethylene production, fruit firmness and quality of ‘Cripps Pink’ apple were investigated. Fruit were harvested from Perth Hills and Donnybrook (Western Australia) at commercial maturity (CM), 2, 4 and 6 weeks after CM prior to 0, 45, 90 and 135 days cold storage in 2003 and 2004. Delayed harvest significantly increased ethylene production, CIE values a* and C* at both locations in 2 years. Delayed harvest and extended cold storage period increased the internal ethylene production and reduced fruit firmness, soluble solids concentration: titratable acidity (SSC:TA) ratio and reduced CIE values L*, b*, h° during both years and locations. Fruit harvested 2 weeks after CM can be cold‐stored for 90 days with acceptable fruit quality. If the fruit is intended to be sold fresh immediately in local markets, the harvest can be delayed up to 6 weeks after CM to harness substantially improved fruit colour with acceptable fruit quality.  相似文献   

15.
目的:研究红烧肉在制作过程中工艺对脂肪氧化和脂肪酸含量变化的影响。方法:以上海本帮、湖南毛氏、东北传统三种工艺红烧肉为研究对象,以其烹制过程中的不同时间(原料肉、炖煮0、30、60、90 min)为取样点,分析三种红烧肉脂肪层脂肪含量、过氧化值、硫代巴比妥酸值和脂肪酸组成的变化。结果:三种工艺红烧肉制作过程中,肥肉层脂肪含量均显著下降(p<0.05),炖煮温度越高,脂肪含量下降越显著;POV值先增大后减小,在炖煮30 min达到最大值;TBA值在炖煮过程中显著增大(p<0.05);亚油酸(C18:2)、油酸(C18:1)、棕榈酸(C16:0)以及硬脂酸(C18:0)是五花肉脂肪中的主要脂肪酸,占总脂肪酸的90%以上,亚油酸(C18:2)含量显著下降,单不饱和脂肪酸含量上升。结论:三种工艺红烧肉制作过程中,脂肪含量下降、脂肪适度氧化、脂肪酸组成改变,红烧工艺对脂肪氧化和脂肪酸含量影响较大。  相似文献   

16.

ABSTRACT

Response surface methodology based on a five‐level, three‐variable central composite rotatable design was used for modeling the effects of preheat treatments on fresh‐cut “Rocha” pear quality. Studied variables were time (t: 0–150 min), temperature (T: 20–50C) and posttreatment storage time (St: 0–20 days, 5C). The quality‐affecting parameters including color, firmness, pH, soluble solid content, and total ascorbic acid content were the monitored dependent variables. Results provide reasonable estimation of the impact of preheat treatments on the quality of fresh‐cut “Rocha” pear and its shelf life. The time–temperature range of 33–41C during less than 20 min was selected as the conditions that best provided surface browning control, without impairing other studied quality parameters, with an estimated 8‐day shelf life period. The achieved kinetic changes of polyphenoloxidase, partial reduction in enzyme activity (ca. 23%) and depletion of phenolic content (ca. 11%) could be responsible for the browning control.

PRACTICAL APPLICATIONS

Minimal processing, namely cutting operations, triggers physiological reactions which limit fresh‐cut Rocha pear shelf life. Superficial browning is one of the major concerns to this industry, and new “clean” methodologies aiming at the inhibition of such reaction and maximization of the product shelf life will benefit not only from product marketability but also will respond to the consumers' demand of “chemical free” products. Heat treatments have been used to improve fresh‐cut commodities' browning resistance. The present work evaluated the use of preheat treatments against this physiological disorder during storage. Results will provide an optimized preheat treatment that grants high‐quality fresh‐cut Rocha pear with suitable shelf life.
  相似文献   

17.
Flax seed oil obtained from the seeds of flax plant (Linum usitatissimum, L.) is an unexploited source which contains ω‐3 and ω‐6 fatty acids. Flax seed oil is hydrolysed with a novel alkaline lipase from Aspergillus fumigatus MTCC 9657 for the removal of unwanted fatty acids and enrichment of ω‐3 fatty acids. An appropriate balance of ω‐3 and ω‐6 polyunsaturated fatty acids and enzymatic enrichment of polyunsaturated fatty acids in diet promote nutrition and health. Fatty acid composition shows that flax seed oil contains about 26.80%, 13.5% and 25.45% of ω‐3 and ω‐6 fatty acids in triglyceride (TG), diglyceride (DG) and monoglyceride (MG), respectively. After 8 h of hydrolysis, ω‐3 content was increased to 39% in TG, showing that unwanted saturated fatty acids are removed. ω‐6 content of triglycerides in flax seed oil also showed 54.76% increase after 8 h of hydrolysis. An enzymatic method of hydrolysis by fungal lipase was developed by this study and achieved to concentrate the essential fatty acids linoleic acid (LA) and α‐linoleic acids (ALA).  相似文献   

18.
Canola oil, with and without added α‐tocopherol and ascorbyl palmitate, was used to deep‐fat frying potatoes once per day for 10 day or once per week for 10 weeks. Changes in chemical and physical properties were monitored. Refractive index, free fatty acids and absorbance at 232 and 270 nm increased with frying time. Smoke point, ‘L’ color index, iodine value and the C18 : 2/C16 : 0 ratio in the oil decreased with the frying time. According to smoke point, which shows the time of the oil should be discarded, canola oil without antioxidant (control) can be used safely 8 times daily or 7 times weekly. For canola oil with antioxidant (oil + α‐tocopherol + ascorbyl palmitate( the smoke point did not decrease below 170°C in both daily and weekly fryings. This showed that canola oil with antioxidant could be used safely at least 10 times for both frying intervals. In both daily and weekly fryings, the addition of 200 ppm α‐tocopherol and 200 ppm ascorbyl palmitate increased the oxidative stability of canola oil.  相似文献   

19.
The sugar, organic acid, amino acid and fatty acid compounds of eight commercial pear cultivars were identified and quantified using high-performance liquid chromatography (HPLC) equipped with RI and UV detectors and gas-chromatography (GC) equipped with FID detector. The mineral composition was determined by inductively coupled plasma-mass spectrometry (ICP-MS). The results showed great quantitative differences in the composition of the pear cultivars. Fructose was the dominant sugar in the eight pear varieties, followed by glucose and sucrose, while malic acid was the principal organic acid. The C16:0, C18:0, C18:1, C18:2 and C18:3 fatty acids were clearly the most abundant fatty acids, and the C18 family comprised more than 70% of the total fatty acids content. Asparagine and serine were the principal amino acids. Potassium is the most abundant mineral, followed by magnesium and calcium. The results provide important information on how to make the best use of pear cultivars investigated for different uses, which is of significance for both technological research and processing practice.  相似文献   

20.
本文研究了用气相色谱/质谱法测定比较3种海参与3种贝类脂肪酸及脂肪醛二甲基缩醛的方法。该6种原料经Folch法提取总脂,用10%硫酸-甲醇溶液对其进行甲酯化反应,通过气相色谱/质谱法对其脂肪酸及脂肪醛二甲基缩醛的组成进行分析。实验结果表明:10%硫酸-甲醇溶液能有效地对脂肪酸进行甲酯化衍生;同时促使烯醚键断裂,并与甲醇发生缩醛反应生成脂肪醛二甲基缩醛。通过气相色谱/质谱分析,从3种海参与3种贝类的气相色谱/质谱图中共鉴定出24种脂肪酸,海参中脂肪酸以C16:0,C16:1(n-7)和C20:4(n-6)为主;贝类中脂肪酸以C16:0,C20:5(n-3)和C22:6(n-3)为主;海参与贝类中脂肪醛二甲基缩醛均以C18:0DMA为主。海参和贝类中的脂肪酸及脂肪醛二甲基缩醛的组成与含量都相差较大。  相似文献   

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