棕榈油和大豆油在油条煎炸过程中品质变化研究

以不同熔点棕榈油和棕榈油―大豆油混合油为原料,以大豆油作对照,通过比较油条外观、口感,筛选出适于煎炸油条的棕榈油,再进一步通过测定油条煎炸过程中油脂样品游离脂肪酸(FFA)、过氧化值(PV)、色泽、极性值(PC)、羰基价(COV)等指标,研究两种油在油条煎炸过程中品质变化情况。研究结果表明,熔点14℃棕榈液油和大豆油都适于煎炸油条,且棕榈液油在煎炸过程中具有比大豆油更好氧化稳定性,仅是其游离脂肪酸(FFA)和色泽上升速率快于大豆油。总的来说,两种油在满足煎炸油质量要求前提下,同等数量棕榈油可比大豆油煎炸更多油条。     

边滤对棕榈油煎炸品质的影响

分析了过滤过程中添加滤油粉对棕榈油煎炸品质的影响。实验表明,滤油粉可使深度煎炸的油脂透光率明显升高,能在一定程度上延长棕榈油的氧化稳定时间;在煎炸过程中适当使用滤油粉,可在一定程度上延长棕榈油的使用时间;但滤油粉不能使深度煎炸的棕榈油品质发生显著的改变。     

亚麻籽油和棕榈液油煎炸油条过程中的品质变化

为了获得亚麻籽油的最适煎炸条件,在（180±5） ℃下,以GB 2716—2018中规定极性化合物含量达到27%为煎炸终点,对亚麻籽油和棕榈液油在油条连续煎炸过程中理化指标进行检测和比较,同时对油条进行感官评定。结果表明：在连续煎炸油条过程中,两种植物油的酸值、总氧化值、极性化合物及聚合物含量均随着煎炸时间的延长而不断增加,但在4 h以内,亚麻籽油极性化合物含量较低;亚麻籽油的极性化合物含量在煎炸13 h后达到27.78%,而棕榈液油的极性化合物含量在煎炸18 h后达到27.27%;相较于棕榈液油,在油条煎炸过程中,亚麻籽油中多不饱和脂肪酸含量不断减少,尤其是α-亚麻酸下降幅度更大;亚麻籽油140 ℃下的氧化诱导期均在1 h以内,远低于棕榈液油;油条感官评定表明棕榈液油更适宜于油条煎炸。研究表明亚麻籽油适合短时（<4 h）高温煎炸,不建议长时间深度煎炸。     

油炸对鸡肉中反式脂肪酸含量及棕榈油品质的影响

以棕榈油作油炸油,油炸表面涂抹蜂蜜水的鸡腿,研究棕榈油连续使用时间对鸡肉中反式脂肪酸含量的影响,并测定棕榈油的酸价和羰基值,探究其品质变化规律。结果表明:以棕榈油作油炸用油,油炸后鸡肉中所含的主要反式脂肪酸为C18∶1 9t;棕榈油使用2~10 h,鸡肉中总反式脂肪酸含量显著增加。棕榈油酸价在油炸过程中一直符合食用油煎炸过程中卫生标准;而羰基值在160℃下使用10 h时达到54.66 meq/kg,超过国标规定的最大限量,180℃下使用8 h即将超标,而200℃时已经超标。因此,以棕榈油进行油炸加工鸡肉时,应选择160℃左右的加工温度,并控制棕榈油使用时间不超过10 h。      

Milk and cheese from cows fed calcium salts of palm and fish oil alone or in combination with soybean products

Twenty cows were used in a randomized block design experiment for 6 wk to determine the influence of feeding partial ruminally inert Ca salts of palm and fish oil (Ca-PFO), alone or in combination with extruded full-fat soybeans or soybean oil, on milk fatty acid (FA) methyl esters composition and consumer acceptability of milk and Cheddar cheese. Cows were fed either a diet containing 44% forage and 56% concentrate (control) or a diet supplemented with 2.7% Ca-PFO (FO), 5% extruded full-fat soybeans + 2.7% Ca-PFO (FOESM), or 0.75% soybean oil + 2.7% Ca-PFO (FOSO). Total dietary FA content in the control, FO, FOESM, and FOSO diets were 4.61, 6.28, 6.77, and 6.62 g/100 g, respectively. There was no difference in nutrient intake, milk yield, or milk composition among treatments. Conjugated linoleic acid (CLA) C_18:2cis-9, trans-11 isomer, C_18:1trans-11 (VA), and total n-3 FA in milk from cows on the control, FO, FOESM, and FOSO treatments were 0.56, 1.20, 1.36, and 1.74; 3.29, 4.66, 6.34, and 7.81; 0.62, 0.69, 0.69, and 0.67 g/100 g of FA, respectively. Concentrations of CLA, VA, and total n-3 FA in cheese were similar to milk. A trained sensory panel detected no difference in flavors of milk and cheese, except for acid flavor below a slightly perceptible level in cheese from all treatments. Results suggest that feeding Ca-PFO alone or in combination with extruded full-fat soybeans or soybean oil enhanced the CLA, VA, total unsaturated and n-3 FA in milk and cheese without negatively affecting cow performance and consumer acceptability characteristics of milk and cheese.     

基于介电常数和低场核磁共振技术的煎炸油品质分析

应用介电常数仪和低场核磁共振分析仪分别测定了150、180、210℃下煎炸棕榈油2～10h(每间隔2h取样)的介电常数和弛豫图谱。将介电常数(ε)结果与GC测定的相应游离脂肪酸含量变化相比较,将弛豫峰面积比例之比(S21/S22)与对应的油酸和棕榈酸比值(O/P)相比较,并进行相关性分析。结果表明,在三个高温的不同时间下,介电常数(ε)可以用于煎炸棕榈油的品质分析;弛豫时间T21、T22可以用来辨别棕榈油是否经过高温煎炸处理;在150、180℃下,S21/S22与O/P在不同时间下的变化趋势相似,呈显著正相关性(p<0.05,p<0.01),可以用于监测这两个温度下煎炸棕榈油劣变程度;在210℃下,S21/S22与O/P变化规律相差较大且无相关性。      

Effect of blending and lipase catalyzed interesterification reaction on the cholesterol lowering properties of palm oil with rice bran oil in rats

The effect of feeding blended and interesterified oils containing palm oil (PO) and rice bran oil (RBO) on serum and liver lipids was evaluated in rats. The PO and RBO were blended to contain saturated, monounsaturated and polyunsaturated fatty acids in the proportion of 1:1.5:1. The blended oil was subjected to transesterification reaction using immobilized lipase, lipozyme IM‐RM. Rats were fed a diet containing blended or interesterified oils for 8 weeks. Rats fed PO showed significantly higher levels of cholesterol in serum and liver as compared to those given RBO, blended oil of PO with RBO or interesterified oil. Rats fed blended oils showed a significant decrease in serum cholesterol by 51% compared to rats fed PO. Feeding interesterified oil to rats resulted in decrease in serum cholesterol by 56% compared to rats fed PO, which was 10% lower compared to that observed in rats given blended oil. The present study indicated that a combination of PO with RBO can significantly lower serum lipids in rats as compared to those given diet containing PO alone.     

煎炸过程对棕榈油品质及南美白对虾中 AGEs含量的影响

以煎炸油和煎炸南美白对虾为研究对象,探究煎炸时间及煎炸物料对煎炸油品质的影响;采用液相色谱-质谱联用及荧光技术测定煎炸对虾中晚期糖基化终末产物（AGEs）的含量,探究煎炸过程对煎炸对虾中AGEs生成的影响。结果表明,高温煎炸可加速棕榈油氧化,使其酸值（AV）、p-茴香胺值（p-AnV）、羰基值（CV）显著增加,24 h时达到最大值。煎炸后,对虾水分含量显著降低,脂肪、丙二醛和荧光AGEs含量显著升高,煎炸批次对其无显著影响。煎炸对虾外层丙二醛、荧光AGEs、非荧光AGEs（羧甲基赖氨酸（CML）、羧乙基赖氨酸（CEL）和甲基乙二醛氢咪唑酮（MG-H1））含量显著高于内部,与未煎炸生虾相比除内部CEL含量有所降低外其余均高于未煎炸生虾。随着煎炸批次的增加,煎炸对虾外层CML、CEL和MG-H1含量均逐渐降低,在煎炸第5批时趋于稳定,煎炸第1批时取得最大值,分别为25.37、335.68 mg/kg和468.20 mg/kg,分别为未煎炸生虾的7、4.5倍和16.5倍;煎炸对虾内部CML、CEL和MG-H1含量均先升高后降低,在煎炸第5批时趋于稳定,煎炸第3批时取得最大值,分别为12.56、85.27 mg/kg和204.20 mg/kg,分别为未煎炸生虾的3.5、1倍和7倍。     

Original article: Antifungal activities of cinnamon oil against Rhizopus nigricans,Aspergillus flavus and Penicillium expansum in vitro and in vivo fruit test

The postharvest pathogens such as R. nigricans, A. flavas and P. expansum are the causal agents of jujube or orange fruit, therefore, in vitro and in vivo antifungal activities of cinnamon oil to inactivate these fungi were investigated. Cinnamaldehyde is the main constituent of cinnamon oil. The minimum inhibitory concentrations of cinnamon oil against Rhizopus nigricans, Aspergillus flavus and Penicillium expansum were 0.64% (v/v), 0.16% (v/v) and 0.16% (v/v), respectively. The antifungal activity of cinnamon oil against A. flavus and P. expansum was stronger than that against R. nigricans and the activity was improved with increasing its concentration. In an in vivo study, cinnamon oil with concentrations of 2.0% (v/v) and 3.0% (v/v) showed complete control the growth of fungi in wound‐inoculated Lingwu Long Jujube and Sand Sugar Orange fruits. These results revealed that cinnamon oil has a good potential to be as a natural antifungal agent for fruit applications.     

Frying of potato chips in a blend of canola oil and palm olein: changes in levels of individual fatty acids and tocols

The changes occurring in the levels of nutritionally relevant oil components were assessed during repeated frying of potato chips in a blend of palm olein and canola oil (1:1 w/w). The blend suffered minimal reductions in omega‐3 and omega‐6 polyunsaturated fatty acids. There was no significant difference between the fatty acid composition of the oil extracted from the product and that of the frying medium, in all three cases. The blend also contained a significant amount of tocols which add a nutritional value to the oil. The concentration of the tocols was satisfactorily retained over the period of oil usage, in contrast to the significant loses observed in the case of the individual oils. The blend also performed well when assessed by changes in total polar compounds, free fatty acids, p‐anisidine value. When fried in used oil, the product oil content increased progressively with oil usage time. This study shows that blended frying oils can combine good stability and nutritional quality.     

初榨橄榄油中的微生物群及其对橄榄油品质的影响

初榨橄榄油生产环境相对开放,榨取橄榄油的原料、环境及设备中的微生物群都可能进入初榨橄榄油,对油脂品质产生影响。为全面认识初榨橄榄油中微生物群以及从微生物层面控制初榨橄榄油品质,从食品微生物学研究的视角,综述了初榨橄榄油中酵母菌、细菌和霉菌等主要微生物群,分析了油橄榄枝叶、果实和初榨橄榄油中的微生物群对油脂品质的影响,介绍了采后储存的油橄榄果实及储存期的初榨橄榄油品质与微生物群之间的关系,探讨了对有害微生物群影响初榨橄榄油品质的防控措施。研究认为酵母菌对初榨橄榄油储存期间的品质起主要的影响作用。通过避免采摘和储存过程中油橄榄果实的损伤,保证加工过程中清洗用水和设备的洁净,控制储存环境温度、光照和氧含量等措施,可以有效防控有害微生物对橄榄油品质的负面影响。     

Feeding of palm oil fatty acids or rapeseed oil throughout lactation: Effects on energy status,body composition,and milk production in Norwegian dairy goats

The objective of this experiment was to examine how supplements of rapeseed oil or palm oil fatty acids would affect milk production and composition, body lipid stores, and energy balance in 30 multiparous goats of Norwegian dairy goat breed. The experiment lasted 230 d, with 1 to 120 d in milk (DIM) for indoor feeding (P1), 120 to 200 DIM for mountain grazing (P2), and 200 to 230 DIM for indoor feeding (P3). Grass silage was fed according to appetite during indoor feeding periods. After an adjustment period (1–60 DIM) when the control diet was given to the goats, the animals were subdivided into 3 groups of 10 goats. Treatments (60–230 DIM) were (1) basal concentrate (control; no added fat); (2) control concentrate with 8% (added on air-dry basis) hydrogenated palm oil enriched with palmitic acid (POFA); and (3) control concentrate with 8% (added on air-dry basis) rapeseed oil (RSO). Individual energy balances based on energy intake and milk production were estimated on 10, 30, 60, 90, 120, 200, and 230 DIM. At the same times, body weight (BW), body condition score (BCS), body mass index, and body tissue stores using computed tomography were monitored. Silage intake was depressed by POFA throughout the experimental period. Reduced BW and body mass index were observed in the POFA and RSO groups, whereas no effect on BCS or body composition was observed throughout lactation. Generally, a minor decrease in BW was observed from 10 to 120 DIM (only 0.6 kg on average) and the total amount of body lipid was reduced by 4.4 kg. During the mountain grazing period, a further reduction in body lipid stores (2.7 kg) was observed, and BW was reduced by 3.9 kg in the same period. The goats mobilized, on average, 72% of their fat reserves during the first 200 DIM. In this period, dietary fat supplementation did not reduce the mobilization of adipose tissue but resulted in greater milk fat yield (2 kg more, on average, compared with the control group). Milk yield was not affected by POFA or RSO supplementation. Milk fat content was higher in the POFA group than in the control and RSO groups. Milk protein and lactose contents were not affected by lipid supplements. In late lactation, a rapid accumulation of fat deposits followed the intense mobilization during the grazing period. Dietary lipid supplements had no effect on milk fat yield at this stage. Milk production depends heavily on the ability to mobilize body lipid stores, and neither POFA nor RSO supplements at rates used in our study affected this mobilization.     

Effect of using interesterified and non-interesterified corn and palm oil blends on quality and fatty acid composition of Turkish White cheese

Chemically interesterified blends (CIB) and non‐interesterified blends (NIB) of corn and palm oils (75%w/25%w) were studied in the production of Turkish White cheese (TWC) to modify the fatty acid composition of traditional product. Milk fat (3%) was replaced by CIB and NIB for 25%, 50%, 75% and 100%. All cheese groups were ripened at 5 °C for 90 days. Samples were taken from each group after 3, 30, 60 and 90 days and analysed for their basic composition, lipolysis and proteolysis. CIB‐incorporated cheeses showed a higher degree of lipolysis than the control sample and the NIB‐incorporated counterparts. Fatty acid composition and sensory properties of the final product showed that the incorporation of CIB and NIB in TWC improved the nutritional content of the product because it altered the fatty acid composition without any adverse effect on sensorial quality. We concluded that in production of TWC, 50% of milk fat could be successfully replaced with CIB and NIB, preferably CIB, because of its superior sensory quality.     

Effect of gamma irradiation on microorganisms and components in empty fruit bunch and palm press fibre of oil palm wastes

The effects of irradiation on microbiological load and chemical components of empty fruit bunch (EFB) and palm press fibre (PPF) were investigated as the preliminary study for upgrading of oil palm wastes to animal feeds by fermentation. The initial contamination of microorganisms in both EFB and PPF was very high and there is no significant difference between the samples collected from various palm oil mills. The dose required to eliminate below the detectable level was more than 15 kGy for total aerobic bacteria, but 5–6 kGy is enough for fungi. The contents of holocellulose and lignin were c 60% and 25%, respectively, in both EFB and PPF, and the change in components by irradiation was small. EFB and PPF have a high water holding capacity suggesting that they are suitable substrates for fermentation. These results show that the irradiation by 5–10 kGy on EFB and PPF is applicable for the pasteurisation of fermentation media without any significant change in components.     

混合植物油加工预制外婆菜及其品质研究

使用棕榈油等几种植物油混合的调和油加工预制湘菜外婆菜,研究了混合植物油配比、外婆菜的氧化稳定性以及胡萝卜素和V_E含量。结果表明:棕榈油和豆油的最适配比为豆油14%、熔点5℃棕榈油9%、熔点18℃棕榈油2%、红棕油0.2%,用该配比加工的外婆菜具有优良的综合感官品质和氧化稳定性,且所加工的外婆菜的胡萝卜素和V_E(总生育酚和生育三稀酚)含量分别高达1.82μg/g和19.42μg/g。豆油和棕榈油混合的植物油可以作为优质外婆菜工业生产用油。     

The effect of palm oil or canola oil on feedlot performance,plasma and tissue fatty acid profile and meat quality in goats

Twenty-four entire male Kacang kid goats were fed diets containing 3% canola (n = 12) or palm oil (n = 12) supplements for 16 weeks. The goats had an initial live weight of 14.2 ± 1.46 kg and were fed a mixed ration ad libitum (10.4 MJ/ME and 14% crude protein). There was no difference in feedlot performance due to diet. Inclusion of canola oil reduced (P < 0.05) kidney fat weight and increased (P < 0.05) linolenic acid (18:3n − 3) concentration in the blood plasma, m. longissimus lumborum (LL), liver, and kidney. The palm oil diet increased (P < 0.05) myristic (14:0) and palmitic (16:0) acid content in the blood, but this did not alter these fatty acids in the LL muscle. Lipid oxidative substances in the liver and LL from palm oil fed kids were higher (P < 0.05) than those from canola supplemented kids. The incorporation of canola oil into the goats' diet increased muscle omega-3 fatty acid content, but lipid oxidation was lowered in the blood and muscle LL.     

Antimicrobial efficacy of citron essential oil on spoilage and pathogenic microorganisms in fruit-based salads

The aim of this study was the evaluation of the effects of pure citral and citron essential oil on microbial spoilage and growth and survival of pathogenic microorganisms during storage. They were added in the syrup of industrial ready-to-eat fruit salads stored at 9 degrees C. Both citral (25 to 125 ppm) and citron essential oil (300, 600, 900 ppm) were able to prolong the microbial shelf life of the fruit-based salads. The essential oil gave excellent results, avoiding the undesirable effects attributable to the cytotoxicity of citral. Citron essential oil doubled the time needed for the wild microflora to reach concentrations able to produce a perceivable spoilage in condition of thermal abuse (9 degrees C). The same essential oil had reduced effects on the survival of Gram-negative species Salmonella Enteritidis and Escherichia coli, but showed a strong inhibition toward the Gram-positive pathogen Listeria monocytogenes.