Effects of drying methods on qualitative and quantitative properties of essential oil of two basil landraces

Sweet basil, a plant that is extensively cultivated in some countries, is used to enhance the flavour of salads, sauces, pasta and confectioneries as both a fresh and dried herb. To determine the effect of drying methods on qualitative and quantitative characteristics of the plant and essential oil of basil, two landraces, Purple and Green, were dried in sunlight, shade, mechanical ovens at 40 °C and 60 °C, a microwave oven at 500 W and by freeze-drying. For comparison, the essential oils of all samples were extracted by hydrodistillation and analyzed using GC and GC–MS. The highest essential oil yields (v/w on dry weight basis) were obtained from shade-dried tissue in both landraces followed by the freeze-dried sample of the purple landrace and the fresh sample of green landrace. Increasing the drying temperature significantly decreased the essential oil content of all samples. Significant changes in the chemical profile of the essential oils from each of the landrace were associated with the drying method, including the loss of most monoterpene hydrocarbons, as compared with fresh samples. No significant differences occurred among several constituents in the extracted essential oils, including methyl chavicol (estragole), the major compound in the oil of both landraces, whether the plants were dried in the shade or sun, oven at 40 °C or freeze-dried, as compared with a fresh sample. The percentage methyl chavicol in the oil, however, decreased significantly when the plant material was dried in the oven at 60 °C or microwaved. In addition, linalool, the second major compound in the purple landrace, and geranial and neral, major compounds in the green landrace, decreased significantly when the plant tissue was dried in the oven at 60 °C or microwaved.     

超临界CO2流体提取洛阳牡丹籽油工艺研究

采用单因素和正交试验法讨论超临界CO2 萃取牡丹籽油过程中萃取温度、压力、时间及CO2 的流量因素对牡丹籽油脂的萃取率及不饱和萃取液中脂肪酸的含量的影响。并采用GC-MS 技术对油脂成分进行分析。结果表明,采用超临界CO2 流体技术可以萃取牡丹籽中的油脂成分,其最佳工艺条件为压力30MPa、萃取温度40℃、萃取时间2.5h、二氧化碳流量25kg/h。此时油脂的萃取率为30.7%,萃取液中不饱和脂肪酸的相对含量可达70.81%。     

Processing Factors Affecting the Yield and Physicochemical Properties of Starch from Cassava Chips and Flour

Three processing factors, namely, raw materials type (RMT) (i.e. chips and flour) and raw material drying mode (RDM) (i.e. sun‐ and oven‐drying at 55 °C) were related to the yield and some physicochemical properties of starch in a 2³ factorial experiment. The quality characteristics investigated were: moisture content, pH, crude fiber content, peak viscosity and pasting temperature. Starch yields from oven‐dried chips and flour were significantly higher (at 5%) than from sun‐dried materials. The optimal yield of 55.9 g (per 70 g of dried product or 79.9%) was obtained from oven‐dried starch extracted from oven‐dried flour. The peak viscosities (PV) of starches extracted from flour and chips were similar while the observed pasting temperatures of flour‐extracted starches were not significantly different from those derived from chips.     

Effect of fruit ripeness and method of fruit drying on the extractability of avocado oil with hexane and supercritical carbon dioxide

BACKGROUND: Oil yield from avocado fruit may be influenced by fruit pre‐treatment and extraction method. Unripe and ripe avocado fruit pieces were deep‐frozen at ? 20 °C and either freeze‐dried or oven‐dried (80 °C). Oil yield from these samples was determined after extraction with hexane and supercritical carbon dioxide (SC‐CO₂). The fruit samples were examined using scanning electron microscopy before and after oil extraction. RESULTS: Average oil yield from ripe fruit (freeze‐dried and oven‐dried combined) was 72 g kg^?1 higher than from unripe fruit for SC‐CO₂ extracts and 61 g kg^?1 higher for hexane extracts. This may be due to enzymatic degradation of parenchyma cell walls during ripening, thus making the oil more available for extraction. Freeze‐dried samples had a mean oil yield 55 g kg^?1 greater than oven‐dried samples for SC‐CO₂ extracts and 31 g kg^?1 higher for hexane extracts. However, oil yields from ripe fruit (freeze‐dried and oven‐dried) subjected to hexane extraction were not significantly different. All hexane extracts combined had a mean oil yield 93 g kg^?1 higher than SC‐CO₂ extracts. CONCLUSION: SC‐CO₂ may be more selective and may create paths of least resistance through the plant material. Hexane, on the other hand, is less selective and permeates the whole plant material, leading to more complete extraction and higher oil yields under the experimental conditions. Copyright © 2007 Society of Chemical Industry     

Optimising drying parameters to maximise omega‐3 essential fatty acid yields in striped weakfish (Cynoscion striatus) industry waste

Fish processing produces high amounts of wastes with low commercial value. Nevertheless, this material could be valorised through the extraction of its polyunsaturated fatty acids. Therefore, the purpose of this study was to evaluate the drying process of striped weakfish (Cynoscion striatus) waste in an air‐circulating oven, aiming to preserve the omega‐3 content. The microbiological and chemical characteristics of the dried product were evaluated. In addition, the lipid quality of the Soxhlet‐extracted oil from the dried material was analysed. The drying condition of 70 °C and 10 h was the most suitable, because it preserved 98.7% of the original content of omega‐3. The dry material presented 14.7% of lipids and 58% of protein, and it was microbiologically safe. The Soxhlet extraction, in spite of using high temperature, did not promote the oxidation of polyunsaturated acids. The applied drying process, followed by Soxhlet extraction, yielded 7.6 g of omega‐3 fatty acids per kg of fresh sample. These results indicate that this residue presents large potential for oil extraction.     

提取黄鳍金枪鱼眼窝肉鱼油的方法比较研究

以黄鳍金枪鱼(Thunnus albacores眼窝肉为研究对象,采用隔水蒸煮法、酶解法、碱水解法和超临界CO2(SC-CO2)萃取法提取鱼油,对所得鱼油的理化性质和脂肪酸组成进行分析测定。结果表明:SC-CO2萃取法和酶解法提取率无显著性差异,但明显高于隔水蒸煮法和碱水解法;SC-CO2萃取法获得的鱼油达到我国水产行业SC/T3502—2000精制鱼油一级标准,其他3种方法达到SC/T3502—2000粗鱼油二级标准;SC-CO2萃取法提取的鱼油不饱和脂肪酸含量最高(74.29%),其中含EPA5.99%、DHA27.12%。因此,SC-CO2较其他3种方法提取金枪鱼眼窝肉中鱼油具有显著优势。     

Short communication: Effects of drying and analytical methods on nitrogen concentrations of feeds,feces, milk,and urine of dairy cows

Nitrogen concentrations in feeds, feces, milk, and urine samples were measured using 2 analytical methods following different drying procedures. Ten samples of corn silage, alfalfa silage, and concentrates collected from 2017 to 2018 at Krauss Dairy Research Center, The Ohio State University (Wooster), were used. A 4-d total collection digestion trial provided fecal samples from 10 cows (1 sample/cow), and another 10 cows were used to collect milk samples (1 sample/cow) and spot urine samples (1 sample/cow). Spot urine samples were acidified immediately to pH <3.0 when collected. Feed samples were oven dried (55°C) or lyophilized and analyzed using the Kjeldahl (KJ; copper sulfate as a catalyst) method and a combustion method (elemental analyzer; EA). Feces, urine, and milk samples were analyzed for N using the following methods: (1) fresh samples by KJ (referred to as wet KJ), (2) lyophilization (urine and milk for 8 h; feces for 120 h) followed by EA (LYO-EA), and (3) oven drying (milk and urine for 1 h; feces for 72 h at 55°C) followed by EA (OD-EA). Additionally, changes in N content of acidified urine at −20° over 180 d of storage were examined. Nitrogen concentrations in corn silage, alfalfa silage, and concentrates were greater for EA by 6.1, 4.8, and 8.3%, respectively, compared with KJ. Analysis of dried samples via EA compared with wet KJ resulted in lower fecal N content (27.8 vs. 29.3 g/kg of DM). Nitrogen concentration in fecal samples via KJ after lyophilization was lower by 5% compared with wet KJ but did not differ from LYO-EA, suggesting that N losses occurred during drying. Nitrogen determination with EA after drying of samples resulted in greater milk N (5.70 vs. 5.50 g/kg) and urinary N (9.16 vs. 9.06 g/kg) content compared with wet KJ. However, drying method (i.e., lyophilization vs. oven drying) did not affect N content of milk, urine, or feces. The use of EA resulted in lower percentage deviation of N content from duplicate sample assays for most samples (no difference was found for concentrate and fecal N), suggesting that EA was more precise than KJ. In conclusion, drying of feces caused N losses regardless of drying methods. For urine and milk samples, if drying is necessary (i.e., EA), oven drying at 55°C can be used rather than lyophilization. The N content was greater in feeds, milk, and urine when determined with EA versus KJ. In addition, N content in acidified and undiluted urine at −20° changed and should be analyzed within 90 d of storage. The results in the current study, however, did not account for laboratory-to-laboratory variation.     

EFFECTS OF PREFRY DRYING METHODS ON THE QUALITY OF DEEP FAT FRIED ONION SLICES

Deep fat fried onion slices are used widely as a condiment for hot-dogs and other types of bread and meat combinations in Denmark, Netherlands and Germany. Since there is a consumer demand for food products, high in both sensory and nutritional quality, the effect of prefry drying on the oil content and the color of the fried product was investigated. In order to reduce the oil content in the fried product, raw sliced onions were prefry dried by (1) hot air in a forced air convection oven, (2) microwaving in an oven with a conveyor belt, or (3) freeze dried. For each of the three methods a series of eight batches ranging from 13–30 % dry matter content in the raw onions were obtained. The product that was dried by hot air before frying was lighter than the product prefry dried by microwaving. The product of the freeze dried material was heterogeneous, and the results were excluded. The fried product from dried raw onions, showed the moisture content to be independent of the manipulated dry matter content. The oil content was reduced from about 55% to about 49%, as a result of increasing the dry matter content; however the surface color became darker (L-value was reduced about 6 point).     

The use of chromic oxide as a food marker —a warning

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.     

The use of low resolution nuclear magnetic resonance for determining avocado maturity by oil content

A method for determining oil content of dried avocado flesh using a low resolution nuclear magnetic resonance (NMR) spectrometer is described. Forty samples were analysed for oil content by NMR, Soxhlet extraction and refractive index (RI) methods. Percentage of oil by NMR was more closely correlated with Soxhlet extracted oil (r=0.978) than was percentage of oil determined by a RI method (r=0.853).
Data from approximately 700 avocado samples collected from the 1975, 1976 and 1978 Queensland growing seasons showed that percentage of oil determined by NMR was better correlated with percentage of dry matter than was percentage of oil determined by RI. Furthermore, the relationships between dry matter and oil were far more consistent between seasons for the NMR method than for the RI one.
Advantages of using the NMR technique in avocados are simplicity, speed, low operator errors and the elimination of the use of dangerous or inflammable solvents. A reproducibility relative standard deviation (s.d.) of 0.6% was obtained.     

Influence of Microwave Treatment of Rapeseed on Minor Components Content and Oxidative Stability of Oil

Rapeseeds were adjusted to moisture contents of 9, 11, 13, and 15 % and treated with microwaves under 800 W for 0, 1, 2, 3, 4, 5, 6, and 7 min at a frequency of 2,450 MHz and oil was extracted with a press to investigate possibility of enhancing oil extraction yield by press, minor component content, and oxidative stability of the pressed oil. The results indicated that microwave pretreatment of rapeseed could increase the oil extraction yield, and both microwave time and initial moisture content of rapeseed had significant effects on the oil extraction yield (p?<?0.001). Total tocopherol content in the oil extracted by press first increased and then decreased depending on the period of microwave radiation (p?<?0.001), and the initial moisture content had no significant effect on the tocopherol content (p?>?0.05). Phytosterol and polyphenol contents increased with increasing microwave time and with decreasing initial moisture content of rapeseeds (p?<?0.001). An F test revealed there were significant interactions between the effects of microwave time and initial moisture content on both polyphenol content and oil extraction yield. The oxidative stability of oil were improved with increasing microwave time and decreasing initial moisture content (p?<?0.001), and there were significant positive correlations with total polyphenol and phytosterol contents. Therefore, it is advisable to treat rapeseeds with low initial moisture content by microwaves prior to oil extraction by press because it results in a relatively good oil extraction yield by cold press, with a high amount of phenolic, tocopherol, and phytosterol. Microwave pretreatment had a positive effect on oxidative oil stability in comparison to the untreated oil.     

超临界-CO2 萃取燕麦麸油及其脂肪酸分析

采用正交试验考察超临界CO2 萃取燕麦麸皮中燕麦油的最佳工艺技术参数,用GC-MS 分析燕麦麸油的脂肪酸组成。结果表明：CO2 超临界萃取的最佳工艺参数为压力15MPa、温度35℃、时间3h,所得燕麦麸油澄清透明,呈金黄色,具有特殊的麦香味。超临界CO2 萃取燕麦麸油中的脂肪酸主要有棕榈酸17.60% 、硬脂酸1.32%、油酸40.15%、亚油酸37.55%、亚麻酸1.89% 和反油酸1.52%;而石油醚萃取燕麦麸油中的脂肪酸主要有15.90%、1.67%、38.38 %、41.67%、1.63% 和1.32%。超临界CO2 萃取与石油醚萃取燕麦麸油中的总不饱和脂肪酸分别占81.11% 和83.00%。     

Characterization of lecithin isolated from anchovy (Engraulis japonica) residues deoiled by supercritical carbon dioxide and organic solvent extraction

Lecithin was isolated and characterized from anchovy (Engraulis japonica) deoiled residues using supercritical carbon dioxide (SC-CO(2)) at a semibatch flow extraction process and an organic solvent (hexane) extraction. SC-CO(2) extraction was carried out to extract oil from anchovy at different temperatures (35 to 45 °C) and pressures (15 to 25 MPa). Extraction yield of oil was influenced by physical properties of SC-CO(2) with temperature and pressure changes. The major phospholipids of anchovy lecithin were quantitatively analyzed by high-performance liquid chromatography. Phosphatidylcholine (PC) (68%± 1.00%) and phosphatidylethanolamine (PE) (29%± 0.50%) were the main phospholipids. Thin layer chromatography was performed to purify the individual phospholipids. The fatty acid compositions of lecithin, PC, and PE were analyzed by gas chromatography. A significant amount of eicosapentaenoic acid and docosahexaenoic acid were present in both phospholipids of PC and PE. Emulsions of lecithin in water were prepared through the use of a homogenizer. Oxidative stability of anchovy lecithin was high in spite of its high concentration of long-chain polyunsaturated fatty acids. PRACTICAL APPLICATION: Lecithin can be totally metabolized by humans, so is well tolerated by humans and nontoxic when ingested. Lecithin from anchovy contain higher amounts of ω-3 fatty acids especially EPA and DHA, it may have positive outcome to use in food and pharmaceutical industries.     

External Fat Cover Influence on Raw and Cooked Beef. 1. Fat and Moisture Content

SUMMARY: The fat content of beef semitendinosus muscle, raw and cooked at two oven temperatures, with and without the external fat cover, has been determined. Each muscle was divided into two, an anterior and a posterior roast. The external fat cover was removed from half of the total number of roasts, and all roasts were then cooked to an internal temperature of 58°C at an oven temperature of either 163° or 218°C. Two types of samples were analyzed for their moisture and fat content. These were a separable lean sample and a total sample. The total sample was composed of both the separable lean and the external fat cover. The moisture content of the lean samples was not affected by the oven temperature, the external fat cover or the end of the muscle used. The total samples had moisture contents that reflected the amount of crude fat present. The yield of crude fat from raw or cooked meat was not significantly altered by the use of a polar solvent in place of a nonpolar one. Both of the fat determination methods extracted significantly more fat from the cooked lean samples than from the comparable raw ones. The lean samples from meat roasted at 163°C contained significantly more extractable fat than the samples roasted at 218°C. The presence or absence of the external fat cover did not affect the amount of fat extracted from the cooked lean.     

Determination of total fat and moisture content in meat using low field NMR

The use of low field Nuclear Magnetic Resonance (LF-NMR) is shown to be a fast and accurate alternative to the use of drying and solvent extraction, to determine the content of raw or total fat and moisture in a biological system. The proposed NMR method for fat determination in minced meat proves to be a robust method that does not require sophisticated post handling of the experimental data. The calibration procedure is very easy, as a calibration value from a sample of known weight containing 100% oil is the only calibration needed for the proposed experimental set-up. On three sets, each containing 42 samples of minced beef where the fat content varies from less than 1 to 14%, the fat content has been measured either by NMR on fresh tissue, NMR on dried tissue, or by the use of solvent extraction determining the content of raw fat [Foss-let fat analyser (AOAC Official Method 976.21]. Comparison of the three methods for determination of the fat content shows satisfactory agreement between the different methods. On six samples of minced pork meat, the fat and moisture content have been determined. The total fat content was determined by NMR both on fresh and dried tissue. The moisture content was determined by NMR of fresh tissue and by drying of the tissue. The different methods for determining fat and moisture content agreed for the minced pork samples.     

南瓜子油的超临界CO_2流体萃取研究

应用超临界CO2 萃取技术 ,研究了南瓜子油的提取工艺 ,着重探讨了原料预处理、萃取压力、温度、萃取时间、CO2 流量对油脂萃取率的影响 ,优化了工艺条件 :压力 3 0MPa ,温度 45℃ ,时间 2 .5h ,CO2 流量 2 5kg/h。利用GC/MS分析了南瓜子油的成分组成 ,比较了超临界CO2 萃取的油样和乙醚萃取油样的理化性质。     

电子舌-固相微萃取-气相色谱-质谱联用比较3 种不同干燥方式对浏阳豆豉品质的影响

以湖南浏阳豆豉为研究对象,比较自然晒制、烘箱烘干和微波烘干3 种不同干燥方式对浏阳豆豉挥发性成分的影响。采用固相微萃取和气相色谱-质谱联用技术结合电子舌,比较3 种不同干燥方式处理的豆豉样品之间差异。结果表明：三者干燥方式理化指标差异不大,自然晒制、烘箱烘干、微波烘干的挥发性成分分别有31、33 种和22 种,自然晒制豆豉主要挥发性成分包括2,3,5,6-四甲基吡嗪（24.10%）、2-甲基丁酸乙酯（19.91%）、2-甲基丁酸（7.82%）、3-甲基-1-丁醇乙酸酯（7.65%）、2,3,5-三甲基吡嗪（7.53%）。烘箱烘干豆豉以乙酸乙酯（3.27%）、2,3-丁二醇（4.23%）、糠基甲基苯丙胺（4.23%）、2-（2-甲基丙基）-3,5,6-三甲基吡嗪（4.13%）、3-辛酮（4.10%）为主。微波烘干豆豉含3-甲基丁酸（27.96%）、2,3,5,6-四甲基吡嗪（13.28%）、2-甲基丁酸（10.55%）、甲酰肼（10.33%）、2,3,5-三甲基吡嗪（6.28%）比例占优。3 种干燥方式后的豆豉味道也有差异,其中自然晒制、烘箱烘干2 种干燥方式处理后豆豉的味道较接近,它们与微波烘干处理方式的差异主要表现在第2主成分上,即鲜味、苦味和咸味。     

Pressing and supercritical carbon dioxide extraction of walnut oil

The objective of this study was to evaluate the oil extraction process from walnut seeds by pressing followed by extraction with supercritical CO₂. In pressing experiments, a factorial arrangement was conducted in order to study the combined effects of seed moisture content (2.5%, 4.5% and 7.5%) and pressing temperature (25, 50 and 70 °C) on oil recovery and quality parameters. For all conditions tested, the oil quality compared well with that of cold-pressed walnut oil. Oil recovery increased significantly as moisture content raised. Highest oil recovery (89.3%) was obtained at 7.5% moisture content and 50 °C temperature. The cake resulting from pressing at these conditions was extracted with CO₂ in a high pressure pilot plant with single stage separation and solvent recycle. The effects of two different pressures (200 and 400 bar) and temperatures (50 and 70 °C) with regard to oil yield and quality, and time required for extraction were analyzed. At each condition, the extraction rate changed with the mass of solvent and extraction time. At first, the mass of oil extracted was determined by the oil solubility in CO₂ and a linear relationship was observed, where the slope results in the solubility of oil in CO₂ at the experiment conditions. After that, the extraction rate was governed by solubility and diffusion, and continuously decreased with time. The colour changed along the extraction from a whitish clear product to a yellow one. Tocopherol and carotenoid contents were significantly higher than those obtained by pressing. Extraction conditions did not affect significantly the fatty acid composition.     

Effects of natural antioxidants in the improvement of corn oil quality: olive leaf vs. lemon balm

Commercially available corn oil was enriched in polyphenols by adding olive leaf and lemon balm extracts, respectively. First, dried and ground plants were extracted through homogeniser‐assisted extraction. Then, the dried extracts were partially dissolved into the corn oil by means of solid–liquid extraction method. Total phenolic content increased 9.5 and 2.5 times over the pure corn oil. The antioxidant activities of enriched oil by olive leaf and lemon balm extracts have been found almost 14 and 6 times higher than that of untreated oil, respectively. Olive leaf extract enhanced the quality better than lemon balm extract with respect to carotenoid (TCC) and chlorophyll contents. Addition of 0.12–0.15% natural antioxidants gave rise to increase in the stability of the oil (≈18%).     

Supercritical carbon dioxide extraction of pelletized Jalapeño peppers

The effects of process pressure (220–500 bar) and temperature (35–65 °C) on yield and extract quality of pelletized Jalapeño peppers (Capsicum annuum L) treated with supercritical carbon dioxide (ScCO₂) were studied. Compaction was inadequate when using whole air‐dried pepper flakes conditioned to high moisture as raw material, which resulted in high porosity pellets and low bed densities. Thus, reference pellet samples were produced from Jalapeño pepper flakes that were finely ground and conditioned to low moisture. Pressures ≥290 bar did not affect cumulative extraction of reference pellet samples at 45 °C. On the other hand, the extraction rate of reference pellet samples at 360 bar increased with process temperature, as a result of increments in solubility, improvements in mass transfer properties, and/or improvements in solute desorption from the solid matrix. With regard to pretreatment, finely ground pepper samples were extracted in half the time of reference pellets (120 versus 270 min) at 360 bar and 45 °C; increasing sample moisture prior to pelletization increased extraction yield; and decreasing particle size prior to pelletization increased extraction rate slightly. These results suggest that sample moisture is partially co‐extracted by ScCO₂, and that the extraction rate of pelletized Jalapeño peppers is controlled by internal mass transfer mechanisms. Chlorophyllian pigments were removed in the final stages of the extraction process. Furthermore, pigment extraction increased with process pressure at 45 °C, and it increased slightly with process temperature at 360 bar. On the other hand, the concentration of capsaicinoids in extract samples remained constant during ScCO₂ extraction. Copyright © 2003 Society of Chemical Industry