Effects of addition of carrot dietary fibre on the ripening process of a dry fermented sausage (sobrassada)

Four formulations of a dry fermented sausage, known as sobrassada, containing different percentages of carrot dietary fibre (DF) [3% (S3), 6% (S6), 9% (S9) and 12% (S12) (w/w)] were analyzed for various physico-chemical and microbiological parameters and sensory attributes. The ripening process was monitored throughout storage. The pH of DF-supplemented sobrassadas was critically affected during ripening by the amount of DF incorporated, the values for sobrassada samples containing over 3% of DF suggested that the fermentation process in these samples was not successful. In addition, textural parameters, such as hardness and compression work, were significantly affected by the addition of over 3% of DF. The lipolytic process, one of the major biochemical events, was only affected when relatively large percentages of DF concentrate were incorporated. Thus, S3 and S6 samples exhibited similar free fatty acid profiles to the control throughout ripening.     

用氢氧化四甲铵作催化剂的毛细管气相色谱法测定香肠中游离脂肪酸

以氢氧化四甲基铵（TMAH）作为催化剂,采用气相色谱进样口热裂解甲酯化分离测定广式香肠中游离脂肪酸的组成和含量,该方法精密准确,操作简便。     

Changes in free amino acids and biogenic amines of Egyptian salted-fermented fish (Feseekh) during ripening and storage

The aim of this study was to investigate changes in the formation of amino acids and biogenic amines in Egyptian salted-fermented fish (Feseekh) during ripening (20 days) and storage (40–60 days). The total concentration of free amino acids increased from 8 (dry weight; DW) to 72 g/kg (DW) after 60 days of storage. The predominant free amino acids were leucine, glutamic acid, lysine, alanine, valine, aspartic acid, isoleucine and citrulline. Their concentrations accounted for 68% of the total concentration of amino acids after 60 days. The total contents of biogenic amines ranged from 84 to 1633 mg/kg (DW) during the investigated period. Cadaverine was the major amine detected in Feseekh at all sampling stages and its concentration varied between 21 and 997 mg/kg (DW). The histamine content (211 mg/kg DW) only exceeded the maximum tolerance level (200 mg/kg) after 60 days. It could be concluded that Feseekh can be consumed without any health risks between 20 and 40 days but it can be hazardous after 60 days due to the biogenic amine content.     

气相色谱法测定亚麻籽中的不饱和脂肪酸

对亚麻籽中脂肪酸含量进行了测定。测定结果表明，亚麻籽中含有大量的不饱和脂肪酸，其中亚油酸3．86g／100g，油酸9．38g／100g，亚麻酸19．34g／100g不饱和脂肪酸总含量达32．58g／100g。     

气相色谱法测定亚麻籽中的不饱和脂肪酸

对亚麻籽中脂肪酸含量进行了测定。测定结果表明,亚麻籽中含有大量的不饱和脂肪酸,其中亚油酸3.86g/100g,油酸9.38g/100g,亚麻酸19.34g/100g不饱和脂肪酸总含量达32.58g/100g。     

Free fatty acids from Lathyrus sativus seed coats acting as short-range attractants to Callosobruchus maculatus (F.) (Coleoptera: Bruchidae)

Lathyrus sativus L. (Leguminosae) seed, commonly known as khesari, is an important legume in India, Pakistan, Bangladesh, China, and Ethiopia. Ten free fatty acids were identified in seed coat waxes of four varieties of L. sativus with total fatty acids accounting for between 10.5 and 17.4 mg per 100 g of seed depending on the variety. Palmitoleic acid (C16:1) was the predominant free fatty acid in two of the varieties; whereas palmitic (C16:0) and lauric (C12:0) acids were the predominant free fatty acids in the two other varieties. Attraction of free fatty acids from seed coat waxes of the four varieties were tested for attractiveness to females of Callosobruchus maculatus (F.) (Coleoptera: Bruchidae) at 2–8, 2–8, 4–8, and 4–8 μg concentrations, respectively, in Y-tube olfactometer bioassays. The attractiveness of synthetic mixtures comparable to the fatty acid compositions of the four varieties were also tested. Individual synthetic myristic, palmitic, palmitoleic, and stearic acids at 0.66, 1.18, 1.36, and 1.18 μg, respectively, elicited attraction of the insect. A synthetic blend of 0.93, 1.68, 1.82, and 1.18 μg of myristic, palmitic, palmitoleic, and stearic acids, respectively, was most attractive to the insect. At present, C. maculatus are controlled with insecticides, which are harmful to human health and environment. Hence, the above mentioned combination of four fatty acids might be used for insect pest management such as baited traps.     

Analysis of free amino acids in cereal products

Free amino acids were extracted from cereal products using 50% ethanol to prevent solubilization of polysaccharides and other viscous polymers and to avoid starch gelatinization. The extracts were analyzed by GC after ion-exchange solid phase extraction and chloroformate derivatization using Ez-Faast technology (Phenomenex). Free amino acids in cereal products could be analyzed within 1 h of extraction and determination, with good separation between peaks and repeatable retention times. Relative correction factor for each amino acid was established. The matrix did not affect the results and the method was repeatable for most of the amino acids (coefficient of variation was in the order of 10%). Different fractions and products of wheat, rye, oats and barely were analyzed. The bran contained more free amino acids than did the other analysed fractions of cereals. Fermentation seemed to consume free asparagine and aspartic acid and to use or release other amino acids.     

气相色谱内标法测定水产饲料中的脂肪酸

建立以十三烷酸为内标物,气相色谱定量测定水产饲料中脂肪酸含量的方法。饲料样品中的油脂经酸热法提取、氢氧化钾-甲醇皂化、三氟化硼-甲醇甲酯化后衍生为相应的脂肪酸甲酯,以SPTM-2560毛细管柱分离,氢火焰离子化检测器测定,保留时间定性、峰面积内标法定量。结果表明,在所选择的色谱条件下,37种脂肪酸甲酯在65 min内获得较好的分离;9种主要脂肪酸加标回收率(n=6)为88.4%~107.5%,相对标准偏差为2.28%~4.79%,最低定量限(S/N=10)为2.0 mg/kg。该方法操作简便、快速、重复性好,适合批量水产饲料样品脂肪酸的定量测定。     

发酵全蛋蛋黄中的脂肪酸组成分析

采用气相色谱测定了发酵全蛋蛋黄中的总脂肪酸及游离脂肪酸的种类和含量,旨在考察发酵对蛋黄脂肪酸的影响。结果从发酵全蛋蛋黄中共检测到22种脂肪酸,其中饱和脂肪酸12种,单不饱和脂肪酸5种,多不饱和脂肪酸5种;共检测到10种游离脂肪酸,其中饱和游离脂肪酸6种,单不饱和游离脂肪酸2种,多不饱和游离脂肪酸2种。与水煮鸡蛋蛋黄相比,发酵全蛋蛋黄中的总脂肪酸及游离脂肪酸的种类均有增加,游离脂肪酸的含量从45.3mg/g增加到54.1mg/g,而总脂肪酸的含量则从273.7mg/g下降至245.2mg/g,说明发酵对蛋黄中的脂肪具有一定的降解作用。      

Generation of volatile flavour compounds as affected by the chemical composition of different dry-cured ham sections

The composition of different dry-cured ham sections has been determined in order to study their contribution to flavour generation. The proteins, free amino acids, free fatty acids and volatile compounds were analysed in different sections of dry-cured hams with 7 and 12 months of processing. The main differences among sections were detected in free amino acids and volatile compounds. To sum up, there was a higher concentration of free amino acids in the centre section than in the butt and shank sections. However, after 12 m of ripening the difference among sections was lower and only the butt was the one with the lowest concentration. Similar results were obtained in the content of volatile compounds, the centre part of the hams contained a higher proportion of volatile compounds after 7 m of ripening than the shank and butt sections. Nevertheless, in 12 months dry-cured hams there are changes in the proportions of volatile compounds being the centre section the one with the highest proportion of volatile compounds due not only to the higher concentration of free amino acids but also to the oxidation of unsaturated fatty acids.