酪蛋白磷酸肽新工艺及其体外功能性质

用Alcalase水解酪蛋白,用TNBS法监测酪蛋白的水解度(DH),运用纳滤技术改善产品质量;同时还研究了不同rN/rP(摩尔比)的CPP(酪蛋白磷酸肽)结合钙离子和亚铁离子的能力.结果表明,用Alcalase酶可以使酪蛋白的水解度(DH)达到16%～20%,TNBS法可以明显减少碱的引入,从而降低CPP产品的灰分含量.截留相对分子质量为150的纳滤膜可以适当的降低CPP产品的rN/rP,改善产品质量,而且能达到80%的总氮回收率;在DH为20%左右,rP基本上没有损失.该工艺适合于工业化生产较高rN/rP的CPP产品.rN/rP较低的CPP结合钙的能力好于rN/rP较高的CPP产品;CPP也可以抑制亚铁离子的沉淀.     

Fatty Acid Content and Antioxidant Properties of Cold-pressed Black Raspberry Seed Oil and Meal

ABSTRACT: Cold-pressed black raspberry seed oil and meal were analyzed for their fatty acid contents and antioxidant properties. The oil contained about 35%α-linolenic acid (18:3n-3) and 55% to 58% linoleic acid. The meal exhibited strong free radical scavenging activities against 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2'-azinobis(3-ethylbenzothiazoline-6-sulfonic acid diammonium salt (ABTS'+) radicals and had a total phenolic content (TPC) of 46 mg gallic acid equivalent/g meal. The ABTS+ scavenging capacity and TPC of the meal were 300 and 290 times greater than that of the oil. In addition, the oil stability iodine value, and color were examined. The results from this study suggest the possible food application of black raspberry seed and its fractions in improving human nutrition and potential value-adding opportunities in black raspberry production and processing.     

基于渗透汽化膜生产脱醇酒的香气成分及功能特性变化

为保证渗透汽化膜生产脱醇酒的品质,将新疆赤霞珠干红葡萄酒原酒经渗透汽化法制得脱醇酒,测定两种样品中香气成分、多酚物质含量、抗氧化指标并进行动物试验,探究脱醇酒香气及其功能特性的变化。结果表明：两种样品中共含有45种香气化合物,其中原酒香气含量为464.36 mg/L,脱醇酒香气含量为301.75 mg/L,脱醇酒总酚、总黄酮、总黄烷-3-醇、总花色苷含量较原酒分别上升21.59%、25.21%、20.00%、35.64%,DPPH、ABTS以及羟基自由基的清除力分别上升17.45%、9.19%、2.82%,动物试验中相较于对照组,原酒与脱醇酒组的大鼠血清中超氧化物歧化酶（Superoxide Dismutase,SOD）分别升高27.43%、74.97%;过氧化氢酶（Catalase,CAT）分别升高224.69%、566.14%;过谷胱甘肽过氧化物酶3（Glutathione Peroxidase-3,GPX3）分别升高21.45%、102.19%。综上,脱醇酒的香气成分保留度较高风味较好,抗氧化等能力都有一定程度提升,说明了脱醇酒具有的功效特性,为脱醇酒产业提升脱醇酒品质提供理论依据。     

L—茶氨酸的功能及在食品加工中的应用

本对L－茶氨酸的生理作用及其作为食品添加剂的应用效果作了详细的论述。     

Microbiological and Chemical Properties of Cheese Helva Produced in Turkey

In this study, the microbiological and chemical properties of Cheese helva, one of the traditional cheeses varieties produced in Turkey, was studied. This cheese is called Cheese helva since it is produced from wheat flour and milk cream. Samples were randomly collected from different villages in the Erzurum province of Turkey. The average of total aerobic mesophilic bacteria (TAMB), yeast and mould, yeast, lactic acid bacteria (LAB), proteolytic bacteria, and lipolytic bacteria were determined 4.9 × 10⁷, 6.4 × 10⁴, 3.5 × 10³, 7.6 × 10⁶, 4.6 × 10³, and 8.6 × 10³ cfu/g, respectively. 44.44% of the Cheese helva samples had no coliform; the samples that were positive for coliform showed an average of 5.1 × 10³ cfu/g. Staphylococcus aureus was found < 10 cfu/g in analyzed samples. The Cheese helva was characterized by dry matter as 84.32 kg/100 kg cheese, fat as 37.44 kg/100 kg cheese, protein as 13.75 kg/100 kg cheese, NaCI as 0.58 kg/100 kg cheese, titratable acidity as 0.210%, pH as 5.30, ash as 1.49 kg/100 kg cheese, and carbohydrate as 38.56 kg/100 kg cheese. Cheese helva was found to have a high variation based on chemical composition. The microbiological tests revealed that there were high amounts of total bacteria, yeast and molds, molds, lactic acid bacteria, lipolytic bacteria, proteolytic bacteria, and coliforms.     

反复冻融对缠丝兔加工过程中脂肪酸含量变化的影响

以反复冻融兔肉为原料,分析缠丝兔加工过程中的脂肪酸含量变化。结果表明：与新鲜原料兔肉对照,随着冻融次数增加,反复冻融原料兔肉及其腌制后和烘烤后的脂肪含量显著降低,硫代巴比妥酸值显著增加（P＜0.05）;原料兔肉检测出棕榈酸（C16∶0）、亚油酸（C18∶2）等脂肪酸,在缠丝兔加工过程中,脂肪降解产生了油酸（C18∶1）;反复冻融兔肉在腌制和烘烤后的脂肪酸也呈显著性变化（P＜0.05）;5 次冻融原料的缠丝兔脂肪含量最低（0.023 8%）、硫代巴比妥酸值最高（0.216 8 mg/kg）。表明兔肉反复冻融对缠丝兔的脂肪酸含量影响显著。     

近红外光谱法结合化学计量学测定油茶籽油中脂肪酸组成

选择97个标称纯油茶籽油样品经过皂化、甲酯化后,先经气相色谱分析得到脂肪酸组成相对含量,然后利用透反射模式采集所有样品的近红外光谱,采用偏最小二乘法(partial least squares analysis,PLS)建立油茶籽油的饱和脂肪酸(C16:0+C18:0)、油酸(C18:1)和亚油酸(C18:2)相对含量的校正模型,并将模型用于预测,并对光谱预处理方法进行优化。结果表明:C16:0+C18:0、C18:1和C18:2的交叉验证均方根误差(root mean square error in cross-vali-dation of prediction,REMSECV)分别为0.143、0.448、0.392,预测均方根误差值(root-mean-square error value,RMSEP)分别为0.180、0.598和0.269,上述3种成分预测集相关系数(Rp2)依次分别为0.996、0.999和0.999。近红外光谱法可作为一种快速、无损和准确的方法用于测定油茶籽油的脂肪酸组成,从而鉴别纯油茶籽油的真伪。     

Physical Indices,Processing Yields,Compositional Parameters and Fatty Acid Profile of Three Species of Cultured Sturgeon (Genus Acipenser)

Cultured Siberian sturgeon (Acipenser baeri), Adriatic sturgeon (Acipenser naccarii) and white sturgeon (Acipenser transmontanus) of market size were examined for condition factor, eviscerated and dressed yields, white flesh yield, viscera-, hepato-somatic- and gonado-somatic indices. Muscle pH, chemical composition, cholesterol content and fatty acid profile of flesh were also determined. Significant differences were noted between species in eviscerated yield and white flesh yield (lowest in A naccarii, highest in A transmontanus), viscera index and gonado-somatic index (lowest in A transmontanus), but not in dressed yield. Muscle lipid content was 77·6, 106·4 and 44·9 g kg^-1 wet weight in A baeri, A naccarii and A transmontanus, respectively. Acipenser baeri had the lowest saturated and the highest polyunsaturated fatty acid content, especially of the ω-3 series (as % total fatty acid methyl esters). Given the differences that emerged under uniform feeding regimen and environmental conditions, it would be reasonable to market the three species under their proper names, rather than under the generic term of ‘sturgeon’ as is presently done in Italy. © 1997 SCI.     

黑花生和白花生中脂肪酸成分的比较

对黑花生和白花生中脂肪酸进行分析比较。采用索氏提取法提取黑花生和白花生中脂肪油,再以氢氧化钾- 甲醇溶液进行甲酯化处理,以气相色谱- 质谱联用仪分离和鉴定脂肪酸的组成和相对含量。结果表明：从黑花生中分离鉴定出19 种脂肪酸,不饱和脂肪酸占61.07%;从白花生中分离鉴定出17 种脂肪酸,不饱和脂肪酸占67.59%。     

两种不同加工方式杨梅汤抗氧化及风味品质比较

杨梅汤是贵州特色的杨梅加工产品。该文以贵州本地产杨梅汤为主要试材,研究了两种不同生产方式生产的杨梅汤的品质,主要测定了维生素C（Vc）、花色苷、总酚、类黄酮以及采用2,2-联苯基-1-苦基肼基（DPPH）和2,2’-联氮双（3-乙基苯并噻唑啉-6-磺酸）二铵盐（ABTS）法测定了杨梅汤的抗氧化性,并对风味及挥发性成分进行了初步探究。结果表明,采用铝罐包装的杨梅汤中Vc,花色苷,总酚,类黄酮,含量在贮藏期间均高于聚丙烯塑料（Polypropylene,pp）罐。在贮藏末期,Vc和花色苷比pp罐高126.50%和37.36%,差异显著。铝罐杨梅汤DPPH清除率及ABTS清除率均强于pp罐。电子鼻风味显示,两者风味基本一致,在贮藏120 d后气味特征完全重叠。铝罐挥发性成分α-石竹烯较pp罐多16.09%,但整体种类略少于pp罐。综上,铝罐包装更有利于杨梅汤贮藏品质的提升。该文研究结果为杨梅汤的生产加工提供理论参数,为提升品质,延长货架期提供理论指导。     

Quality Properties,Fatty Acids,and Biogenic Amines Profile of Fresh Tilapia Stored in Ice

This work determines quality properties and fatty acids content of Nile tilapia (Oreochromis niloticus) stored in ice for 21 d. The quality properties consist of thiobarbituic acid (TBA), total volatile basic nitrogen (TVB‐N), trimethylamine (TMA), and microbiological analysis (total viable count (TVC), total coliform, Salmonella and Staphylococcus aureus) and determination of biogenic amines content (histamine, cadaverine, putrescine, spermine, spermidine, 2‐phenylethylamine, agmatine, tyramine, and ammonia). Moreover, the fat, moisture, and ash composition as well as fatty acids profile have also been analyzed. The TBA, TVB‐N, and biogenic amines analysis showed rather low levels of spoilage even after 21 d of storage. The microbiological analysis, however, showed that tilapia was unsuitable for consumption after just 10 d. The fat, ash, moisture, and fatty acids profile analysis showed that tilapia is not a good source of n?3 fatty acids. The research indicated that the microbiological analysis was the best method to establish spoilage of tilapia stored in ice, of all analytical methods performed in this study.     

Effects of Elaidic Acid,a Predominant Industrial Trans Fatty Acid,on Bacterial Growth and Cell Surface Hydrophobicity of Lactobacilli

The consumption of trans fatty acids (TFAs) increases the risk of cardiovascular diseases and coronary heart disease in human, and there are no effective ways to remove TFAs after consumption. The aim of this study was to investigate the effects of elaidic acid on bacterial growth, cell surface hydrophobicity of lactobacilli, and metabolism of elaidic acid by lactobacilli. Lactobacilli were inoculated in MRS broth containing 0, 100, 200, and 500 mg/L of elaidic acid. Viable cell counts of lactobacilli were enumerated, concentrations of elaidic acid were determined, and cell surface hydrophobicity of lactobacilli was measured. The results showed that the growth of lactobacilli was significantly inhibited by 500 mg/L of elaidic acid, however, a cell count of 8.50 log₁₀ CFU/mL was still reached for tested lactobacilli after 24‐h incubation. In particular, a reduction of elaidic acid was found for tested lactobacilli after 24‐h incubation as compared to its initial concentration of 200 mg/L. However, cell surface hydrophobicity showed no correlations with the metabolism of elaidic acid by lactobacilli. Moreover, elaidic acid was able to influence cell surface hydrophobicity, and the decrease in hydrophobicity was more obvious in Lactobacillus paracasei and Lactobacillus casei compared with that in other tested lactobacilli. This study suggests that elaidic acid could change physiochemical surface properties of lactobacilli and the lactobacilli have the potential to reduce TFAs.     

黑鲷与真鲷及其杂交子一代脂肪含量测定与脂肪酸成分分析

为了解真鲷、黑鲷及杂交子代的脂肪和脂肪酸含量与成分,采用索氏抽提法分析4 种鲷鱼肝脏、肌肉和鱼骨的脂肪含量,气相色谱法分析脂肪酸组成。结果表明,正、反杂交子代均良好地继承了亲本真鲷的优势,脂肪含量明显高于亲本黑鲷,且以肝脏中最为显著。杂交后代与亲代的饱和脂肪酸成分组成情况基本吻合,杂交后代中产生了C12∶0、C22∶0、C24∶0等几种亲代脂肪酸成分中未检测到的脂肪酸,说明杂交后代脂肪酸组成更丰富。杂交后代的不饱和脂肪酸组成与黑鲷亲本基本相同,尤其体现在肝脏组成上。     

Phenolics,Aroma Profile,and In Vitro Antioxidant Activity of Italian Dessert Passito Wine from Saracena (Italy)

A traditional sweet dessert wine from Saracena (Italy), made with nonmacerated local white grapes (Guarnaccia, Malvasia and Moscato), was analyzed for phenolics and aroma profile and antioxidant activities. The most abundant classes of phenols identified by high‐performance liquid chromatography were hydroxybenzoic acids and flavan‐3‐ols, where gallic acid showed the highest content (376.5 mg/L). The analysis by solid phase microextraction‐gas chromatography‐mass spectrometry revealed the presence of superior alcohols (from iso‐butanol and iso‐amyl alcohol up to 2‐phenylethanol) and their ethyl esters, terpenes (such as linalool), furfuryl compounds, and free fatty acids (up to palmitic acid) as the key odorants of this wine. The antioxidant activity, evaluated by different in vitro assays 2,2‐diphenyl‐1‐picrylhydrazyl (DPPH), 2,2′‐azino‐bis(3‐ethylbenzothiazoline‐6‐sulphonic acid (ABTS), and β‐carotene bleaching test), showed that passito wine had a radical scavenging activity (IC₅₀ value of 0.03 v/v against DPPH·) and inhibited linoleic acid oxidation with an IC₅₀ value of 0.4 v/v after 30 min of incubation.     

Physical,Textural, and Antioxidant Properties of Extruded Waxy Wheat Flour Snack Supplemented with Several Varieties of Bran

Wheat represents a ubiquitous commodity and although industries valorize 10% of wheat bran, most of this antioxidant‐rich byproduct gets fed to livestock. The objective of this study was to incorporate wheat bran into an extruded snack. Bran samples from hard red spring, soft white club cv. Bruehl, and purple wheat lines were added to cv. Waxy‐Pen wheat flour (Triticum aestivum L.) at replacement concentrations of 0%, 12.5%, 25%, and 37.5% (w/w; n = 10). Extrudates were evaluated for antioxidant capacity, color, and physical properties. Results showed that high fiber concentrations altered several pasting properties, reduced expansion ratios (P < 0.0001), and created denser products (P < 0.0001), especially for white bran supplemented extrudates. Purple bran supplemented extrudates produced harder products compared to white and red bran treatments (P < 0.0001). Extrudates produced with 37.5% (w/w) of each bran variety absorbed more water than the control with no added bran. The oxygen radical absorption capacity assay, expressed as Trolox Equivalents, showed that extrudates made with addition of red (37.5%) and purple (37.5%) bran had higher values compared to the other treatments; the control, red, and white bran treatments had less antioxidant activity after extrusion (P < 0.0001) compared to purple bran supplemented extrudates. Purple and red brans may serve as viable functional ingredients in extruded foods given their higher antioxidant activities. Future studies could evaluate how bran variety and concentration, extruded shape, and flavor influence consumer acceptance.