蛋类的不同加工工艺对脂肪、胆固醇含量的影响

蛋类通过醋泡、碱制等不同的加工工艺使之变成功能性食品醋蛋、松花蛋。通过测定其加工前后胆固醇、脂肪的含量,发现加工后胆固醇、脂肪含量大大低于加工前的含量。试验结果表明,不同醋处理鸡蛋中脂肪含量下降幅度在7.50%～11.69%;碱处理鹌鹑蛋、鸭蛋脂肪含量下降分别为34.34%、16.81%～35.28%;碱处理鹌鹑蛋、鸭蛋胆固醇含量下降分别为27.46%、48.93%～76.42%;醋处理鸡蛋中胆固醇含量下降幅度在13.02%～73.39%。      

降低肉制品脂肪,胆固醇含量的研究

利用胆固醇在紫外线照射下生成不溶性ＶＤ３和饱和脂肪酸在紫外线照射下产生游离基而发生聚合反应，生成更稳定分子的原理，对红色肉进行处理，再加工成品，可以制成低脂肪、低胆固醇的肉制品。     

不同麦麸材料吸附脂肪和胆固醇的研究

目的探讨黑曲霉固体发酵麦麸、液体发酵麦麸和酶解(多糖水解酶和阿魏酸酯酶)麦麸的持水力、对脂肪和胆固醇的吸附作用,为其在食品中的应用提供依据.方法采用离体法.主要结果麦麸经发酵和酶解后,持水力和对脂肪的吸附能力大大增加,酶解后持水力增加1倍以上,对脂肪的吸附能力增加48.7%.固体发酵麦麸和酶解麦麸对鸡蛋中胆固醇的吸附能力大大高于原麦麸,而液体发酵麦麸则差于原麦麸.扫描电镜观察结果表明,发酵或酶解后麦麸的上述物性之所以发生较大改变,其主要原因是由于麦麸的内、外结构产生了较大变化.     

黄酒对高血脂大鼠血清总胆固醇含量的影响

通过动物实验，对黄酒的降血清胆固醇功能进行了初步研究。给雄性SD成年大鼠喂高胆固醇饲料，造成高血脂动物模型，再给模型鼠按不同剂量灌喂浓缩的黄酒。结果显示，黄酒浓缩物具有降血清胆固醇的作用。     

不同麦麸材料吸附脂肪和胆固醇的研究

目的：探讨黑曲霉固体发酵麦麸、液体发酵麦麸和酶解(多糖水解酶和阿魏酸酯酶)麦麸的持水力、对脂肪和胆固醇的吸附作用，为其在食品中的应用提供依据。方法：采用离体法。主要结果：麦麸经发酵和酶解后，持水力和对脂肪的吸附能力大大增加，酶解后持水力增加1倍以上，对脂肪的吸附能力增加48．7％。固体发酵麦麸和酶解麦麸对鸡蛋中胆固醇的吸附能力大大高于原麦麸，而液体发酵麦麸则差于原麦麸。扫描电镜观察结果表明，发酵或酶解后麦麸的上述物性之所以发生较大改变，其主要原因是由于麦麸的内、外结构产生了较大变化。     

凝固型降胆固醇全蛋发酵饮料加工工艺研究

目的：以鲜鸡蛋为主要原料，通过乳酸菌发酵作用加工凝固型降胆固醇发酵全蛋饮料；方法：对嗜热链球菌、保加利亚乳杆菌、嗜酸乳杆菌、两岐双岐杆菌及其复合菌种的降胆固醇能力进行测定，选择嗜热链球菌和保加利亚乳杆菌作为复合发酵菌种，对发酵基质配方和发酵条件进行优化；结果：确定全蛋液用量32％、葡萄糖用量1．25％、CMC—Na用量0．3％、卡拉胶用量0．2％、培养时间24h为优选条件，在优选条件下胆固醇降解率可达36．03％，且感官质量较好。     

江蓠藻膳食纤维吸附脂肪、胆固醇和胆酸钠的研究

比较江蓠藻水溶性膳食纤维、水不溶性膳食纤维和总膳食纤维对脂肪、胆固醇和胆酸钠的体外吸附作用.结果表明,3种膳食纤维对脂肪、胆固醇和胆酸钠均有一定的吸附作用,其中,江蓠藻水溶性膳食纤维对于胆固醇和胆酸钠的吸附能力大于另2种膳食纤维,对脂肪的吸附作用,江蓠藻水不溶性膳食纤维也要强于另2种膳食纤维.说明江蓠藻膳食纤维能减少机体对膳食中脂肪、胆固醇的摄入.     

不同加工方式与时间对猪肉脂肪含量和脂肪酸组成的影响

为研究不同加工方式和时间对猪肉脂肪酸组成、脂肪含量、营养及风味的影响,以PIC猪背最长肌为原料,经不同时间的蒸煮或烤制加工后,分别测定各样品的脂肪含量和脂肪酸组成。结果显示,加工时间主要影响PUFA/SFA和SFA+MUFA值、磷脂的含量和脂肪酸组成、肌内总脂肪酸的组成;加工方式主要影响肌内脂肪总含量、甘三酯的含量、游离脂肪的脂肪酸组成;游离脂肪酸的含量同时受加工时间和方式的影响,而甘三酯的脂肪酸组成在加工中没有明显变化。因此采用不同时间的蒸煮或烤制加工时,加工方式和时间都会对猪肉脂肪酸组成、脂肪含量、营养及风味产生影响,但加工时间对脂肪酸组成、营养和风味的影响更大,而加工方式对脂肪含量的影响更显著。     

不同加工方式与时间对猪肉脂肪含量和脂肪酸组成的影响

为研究不同加工方式和时间对猪肉脂肪酸组成、脂肪含量、营养及风味的影响,以PIC猪背最长肌为原料,经不同时间的蒸煮或烤制加工后,分别测定各样品的脂肪含量和脂肪酸组成。结果显示,加工时间主要影响PUFA/SFA和SFA+MUFA值、磷脂的含量和脂肪酸组成、肌内总脂肪酸的组成;加工方式主要影响肌内脂肪总含量、甘三酯的含量、游离脂肪的脂肪酸组成;游离脂肪酸的含量同时受加工时间和方式的影响,而甘三酯的脂肪酸组成在加工中没有明显变化。因此采用不同时间的蒸煮或烤制加工时,加工方式和时间都会对猪肉脂肪酸组成、脂肪含量、营养及风味产生影响,但加工时间对脂肪酸组成、营养和风味的影响更大,而加工方式对脂肪含量的影响更显著。      

几种市售膳食纤维对脂肪、胆固醇、胆酸盐、亚硝酸根离子吸附作用的研究

目的:研究几种市售膳食纤维对脂肪、胆固醇、胆酸盐、亚硝酸根离子的吸附能力。方法:采用体外实验模拟人体胃和小肠的pH条件,以天然小麦麸为对照,测定四种市售膳食纤维制品对脂肪、胆固醇、胆酸盐、亚硝酸根离子的吸附量。结果:小麦麸和魔芋纤维吸附脂肪的能力最强;魔芋纤维吸附胆固醇的能力最强;大豆纤维吸附胆酸盐的能力最强;小麦麸吸附亚硝酸盐的能力最强。在胃pH环境下几种膳食纤维吸附亚硝酸盐的能力显著高于小肠pH环境。结论:四种膳食纤维制品均具有较强的吸附能力,但其吸附效果与天然小麦麸相差不大。     

Effect of processing and storage of Jameed on conjugated linoleic acid content and fat and cholesterol oxidation

The influence of Jameed processing and storage on fat and cholesterol oxidation, hydrolytic rancidity, and conjugated linoleic acid (CLA) was evaluated by determining peroxide value (PV), 7-ketocholesterol, free fatty acids content (FFAs) and total CLA. Three different sizes of Jameed pieces (ca. 50, 200 and 400 g balls) were used to investigate the influence of storage for 0, 1, 3, 5 and 7 months on the above lipid oxidation parameters. No significant (P>0.05) effect of the Jameed processing steps on lipid changes was found with the exception of the sun drying steps, that caused an increase of PV, 7-ketocholesterol and FFA contents and a decrease in CLA content. This trend was also observed during storage of Jameed at room temperature and kept exposed to light and atmospheric air. The PV values of the 50, 200 and 400 g balls after 7 months of storage were 35.3, 19.4 and 20.4 meq O₂ kg⁻¹ of fat, that were 17, 11 and 12 times higher compared with the corresponding values of the fresh samples (1.9 meq O₂ kg⁻¹ of fat ). The 7-ketocholesterol of the tested samples increased from about 5.7 μg g⁻¹ to 210, 120 and 125 μg g⁻¹ for the 50, 200 and 400 g balls, respectively. FFA content increased remarkably during storage, from about 1.3 g kg⁻¹ at the beginning of storage to 8.6 g kg⁻¹ of fat after 7 months with no significant (P>0.05) effect for the size of Jameed pieces on FFAs content. On the contrary, a decrease of about 43%, 26% and 26% of the original value (5.7 mg kg⁻¹ of fat) in CLA content was found for the stored Jameed pieces of 50, 200 and 400 g, respectively.     

The gerber method: Its suitability for determining the fat content of egg products

Summary The best results were obtained by using a different sulphuric acid concentration for each product, viz. ^24° _4° 1.58 for whole egg, ^24° _4° 1.53 for yolk, and ^24° _4° 1.48 for whole egg powder. By employing hydrolysis with hydrochloric acid instead of sulphuric acid too low fat contents can be prevented. It was shown that too high fat contents were due to amyl alcohol, added before the centrifuging of the fat. This is attributed to the formation of a significant amount of amyl esters from the phospholipid fatty acids released during hydrolysis. Ester formation with amyl alcohol was demonstrated by means of thin layer chromatography. It is concluded that when sulphuric acid and amyl alcohol are used the method is, in fact, not suitable for egg products.[/p]

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Zusammenfassung Die besten Ergebnisse wurden erzielt, wenn für jedes Eiprodukt Schwefelsäure verschiedener Stärke benutzt wurde: für Vollei ^24° _4° 1.58, für Eigelb ^20° _4°. 1.53 und für Trockenvoller ^20° _4° 1.48. Wenn die Hydrolyse mit Salzsäure statt mit Schwefelsäure ausgeführt wird, können zu niedrige Fettgehalte vermieden werden. Es zeigte sich, daß zu hohe Gehalte durch den Zusatz von Amylalkohol beim Zentrifugieren des Fettes in dem Butyrometer verursacht werden. Dies wird mit der Bildung einer gewissen Menge von Amylestern aus den bei der Hydrolyse freiwerdenden Fettsäuren der Phospholipiden erklärt. Die Esterbildung mit Amylalkohol wurde mit Hilfe der Diinnschichtchromatographie nachgewiesen. Die Gerber-Methode ist be iVerwendung von Schwefels\:aure und Amylalkohol genau genommen f\:ur Eiprodukte nicht geeignet.[/p]

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The author wishes to thank Mr. A. Kraal for his experimental and analytical assistance.     

不同加工精度对大米中镉含量的影响

将46组稻谷用砻谷机砻谷后得到糙米,再用碾米机碾去糙米的糠层,根据碾米时间的不同,将稻谷分为糙米、四级精米、三级精米、二级精米、一级精米,三级糠粉和一级糠粉;用原子吸收分光光度计测定46组大米各组分的镉含量并进行分析,得出镉含量的大小顺序为：三级糠粉>一级糠粉>糙米>四级精米>三级精米>二级精米>一级精米;通过将大米中各组分两两比较进行配对样本T检验,得出一级糠粉与糙米具有统计意义(P＜0.05),其余比较分析具有较大差异性(P＜0.01);不同加工精度的精米中重金属镉含量也存在显著差异：四级精米镉含量最高,为(0.40±0.24)mg/kg,一级精米镉含量最低,为(0.22±0.13)mg/kg;稻谷的糠层对镉的富集作用最强,对于整个稻米镉含量分析有较大影响。     

Effect of solvent to sample ratio on total lipid extracted and fatty acid composition in meat products within different fat content

The effect of solvent to sample ratio on total extracted lipids and fatty acid (FA) composition in meat products with different fat contents was evaluated. Total lipids were extracted according to the Folch et al. (1957) method, using a 20:1 ratio of chloroform:methanol (2:1, v/v) to sample (A), and also testing the solvent:sample ratio of 10:1 (B). Higher amounts of total lipids and total FA from neutral lipids were obtained using the A ratio, which could be due to an insufficient chloroform:dry-weight sample proportion which could be insufficient for solubilizing the total amount of lipids. In the polar lipid fraction, the total amount of FA was higher using the B rather than the A ratio, which may be caused by the higher volume of added water when using A than B. When studying the FA composition of different lipid fractions, the volume of both the solvent and the water for total lipid extraction should be considered.     

Effect of fat content on aroma generation during processing of dry fermented sausages

Dry fermented sausages with different fat contents were produced (10%, 20% and 30%). The effect of fat content and ripening time on sensory characteristics, lipolysis, lipid oxidation and volatile compounds generation was studied. Also, the key aroma components were identified using gas chromatography (GC) and olfactometry. High fat sausages showed the highest lipolysis and lipid oxidation, determined by free fatty acid content and thiobarbituric acid reactive substances (TBARS), respectively. A total of 95 volatile compounds were identified using SPME, GC and mass spectrometry (MS). Fat reduction decreased the generation of lipid derived volatile compounds during processing while those generated from bacterial metabolism increased, although only at the first stages of processing. The consumers preference in aroma and overall quality of high and medium fat sausages was related to the aroma compounds hexanal, 2-nonenal, 2,4-nonadienal, ethyl butanoate and 1-octen-3-ol which contributed green, medicinal, tallowy, fruity and mushroom notes.     

不同加工工艺对燕窝产品唾液酸含量的影响

本文以毛燕为原料,研究浸泡、挑拣、高温灭菌等工艺流程处理后燕窝唾液酸含量的变化。采用LC-MS/MS检测分析燕窝中唾液酸种类,此外,测定了不同加工条件下燕窝产品唾液酸含量并分析加工条件对唾液酸含量的影响,进一步分析了唾液酸热稳定性。结果表明:燕窝中唾液酸仅由N-乙酰基神经氨酸（Neu5Ac）组成,经不同工艺条件处理后,Neu5Ac保留率均可高达95%以上,且Neu5Ac热稳定性好,不同情况下Neu5Ac含量无明显差异。说明燕窝经过上述加工处理后不会造成燕窝酸的大量流失,并且其受工艺条件变化影响小,燕窝加工产品可以很好地保存燕窝的营养价值,从而稳定发挥其营养功效,具有很高的消费价值。      

Effect of processing and storage of brined white (Nabulsi) cheese on fat and cholesterol oxidation

Brined white (Nabulsi) cheese was studied for cholesterol oxidation and for oxidative and hydrolytic rancidities during cheese processing, during storage in closed transparent and light‐protected glass jars at room temperature for 3, 6 and 9 months and during storage on an open tray exposed to atmospheric air and light for 1, 2 and 3 weeks. The peroxide value (PV), free fatty acid (FFA) content and 7‐ketocholesterol level were determined. The cheese processing steps (curd formation, salting and boiling in brine) had no significant effect on PV, FFAs and 7‐ketocholesterol. However, the storage conditions had a significant effect (p ≤ 0.5) on these parameters. Peroxides were not detected or were very low in the freshly boiled cheese, while the FFA content was 2.9 g kg^?1. The PV and FFA content increased to approximately 5 meq kg^?1 and 11 g kg^?1 respectively after 9 months of storage in transparent or light‐protected jars. The 7‐ketocholesterol level was 1.2 µg g^?1 in the freshly boiled cheese and reached maximum values of 2.3 and 5.2 µg g^?1 after 9 months of storage in light‐protected and transparent jars respectively. Cheese samples displayed on an open tray showed a higher increase in PV, FFAs and 7‐ketocholesterol than samples stored in closed jars, reaching values of 6.1 meq kg^?1, 6.8 g kg^?1 and 8.8 µg g^?1 respectively after 3 weeks of storage. © 2002 Society of Chemical Industry     

Influence of chitosan feeding of laying hens on egg vitamin and cholesterol content

Chitosan feeding (10 and 20 mg per 1 kg body mass) of 19 week-age laying hens during 1.5 months caused a decrease in whole egg content of vitamin A for 13% and 20% (p < or = 0.05), vitamin E--for 30%, lutein--17% and didn't effect on vitamin B2 level. Chitosan intake lead to cholesterol content 1.5-2 fold decrease and didn't influence on egg yolk lipids concentration. Low dose chitosan-receiving hens had eggs with 1.8-fold increased egg yolk phospholipids level. The most optimal dose of chitosan for the improvement of eggs nutritive value was 10 mg. Under minimal loss in vitamins its administration lead to the pronounced cholesterol decrease and marked phospholipids elevation.     

Determination of lysozyme content in eggs and egg products using SDS-gel electrophoresis

Summary Lysozyme can be separated commercially from other egg components and is used as a natural, antibiotically active protein. A method for the detection of de-lysozymed egg products using SDS-polyacrylamide gel electrophoresis (PAGE) is described. The method can also be used for lysozyme quantification. Lysozyme concentrations in egg products are tentatively assigned to three classes, based on the lysozyme contents found in intact eggs. The results obtained from a series of egg products on the market allow two groups to be distinguished. The first group has values for average lysozyme content, standard deviation and total protein content very close to the values found for intact eggs, and the second group clearly shows a lower lysozyme content but a total protein content comparable with intact eggs.

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Elektrophoretische Bestimmung von Lysozym in Eiern und Eiprodukten

Zusammenfassung Lysozym wird aus Eiern kommerziell entfernt zu anderweitiger Nutzung als natürliches, antibiotisch wirksames Protein. Zur Unterscheidung von unveränderten und entlysozymierten Eiprodukten wird eine SDS-Polyacrylamid-Gelelektrophoresemethode (PAGE) beschrieben, welche auch zur quantitativen Lysozymbestimmung herangezogen werden kann. Aufgrund der in ganzen Eiern bestimmten Lysozymgehalte werden 3 Beurteilungsbereiche für den Lysozymgehalt von Eiprodukten vorgeschlagen. Die Resultate einer Meßreihe von Handelsmustern zeigen zwei Gruppen: Eine mit sehr guter Übereinstimmung von mittlerem Lysozymgehalt, dessen Streubereich und Gesamtproteingehalt, und eine zweite Gruppe mit klar abweichendem Lysozymgehalt, aber Gesamtproteingehalten in der gleichen Größe wie die erste Gruppe.