黄参酒生产工艺优化及香气成分研究

以山丹黄参为原料,对黄参酒的生产工艺进行了优化。研究了料液比、辅料种类、酿酒曲种类及发酵时间对黄参酒品质的影响,结合感官评定,确定最佳的生产工艺条件,并使用气相色谱-质谱（GC-MS）联用技术对黄参酒的香气成分进行检测。结果表明,最优工艺条件为:黄参∶水比例为1∶100（g/m L）,淀粉为辅料,酒曲为清香型酒曲,发酵周期14 d;初步定性出60种化合物。其他理化指标显示所得黄参酒品质较好。      

Effect of γ-Oryzanol on the Flavor and Oxidative Stability of Refrigerated Cooked Beef

ABSTRACT: γ-Oryzanol and α-tocopherol were added to beef patties as natural antioxidants. Beef patties containing 100 ppm γ-oryzanol had higher oxidative stability ( P <0.05) during storage at 4 °C than did beef patties with other antioxidants and without antioxidant. Thiobarbituric acid-reactive substances (TBARS) values, warmed over flavor (WOF) scores, C-7 oxidized cholesterol derivatives (OCDs), and concentrations of both hydroperoxide and hexanal in the cooked beef containing γ-oryzanol were significantly lower than those of other treatments ( P < 0.05). All variables had similar trends during the refrigerated storage. Significant correlations were found between TBARS and C-7 OCDs, TBARS and WOF, hydroperoxide and hexanal, and hexanal and WOF ( P < 0.05).     

Studies on melanoidin-type colorants generated from the Maillard reaction of protein-bound lysine and furan-2-carboxaldehyde – chemical characterisation of a red coloured domaine

 The identification of a coloured substructure of melanoidin-type colorants is reported in the present paper. Brown-orange melanoidins with mass >10000 daltons were isolated from a thermally treated aqueous solution of casein and furan-2-carboxaldehyde using ultracentrifugation. After complete enzymatic digestion of the protein skeleton, two intense red coloured compounds were detected in the melanoidin hydrolysate by HPLC. These compounds were identified as the previously unknown chromophoric amino acid (S)-2-amino-6-{4-[(E)-1-formyl-2-(2-furyl)ethenyl]-5-(2-furyl)-2-[(E)-(2-furyl) methylidene]-2,3-dihydro-3-oxo-1H-pyrrol-1-yl}hexanoic acid and its 2-[(Z)-(2-furyl)methylidene] isomer, by using several NMR techniques, by MS, UV, and IR spectroscopy. The identification of these novel compounds verifies the idea that melanoidin-type colorants can be generated by a cross-linking reaction between a low molecular weight chromophore and a non-coloured high molecular weight biopolymer. Received: 19 August 1997 / Revised version: 24 October 1997     

Total determination of residual flutolanil and its metabolites in livestock products and seafood using liquid chromatography-tandem mass spectrometry

ABSTRACT

We have developed a simple and sensitive LC-MS/MS analytical method for the determination of residual flutolanil and its principal metabolites, including α,α,α-trifluoro-3′-hydroxy-o-toluanilide (M-4) and its conjugates, in livestock and seafood products. Both flutolanil and its metabolites contain the 2-(trifluoromethyl)benzoic acid (2-TFMBA) moiety. In this method, flutolanil and its metabolites are converted to 2-TFMBA by hydrolysis. The method involves direct hydrolysis with sodium hydroxide at 200°C, acidification, partitioning into a mixture of ethyl acetate-n-hexane (1:9, v/v), clean-up using a strong anion exchange cartridge (InertSep SAX), and then quantification using LC-MS/MS. The optimal conditions for the complete hydrolysis of flutolanil to 2-TFMBA are an incubation time of 6 h and a temperature of 200°C. The developed method was evaluated using seven types of food: bovine samples of muscle, fat, liver and milk, as well as egg, eel, and freshwater clam. Samples were spiked both at 0.01 mg/kg and at the Japanese maximum residue limit (MRL) established for each food type. The validation results show excellent recoveries (88–107%) and precision (< 10%) for flutolanil and M-4. The limit of quantification (S/N ≥ 10) of the developed method is 0.01 mg/kg. The developed method is applicable to the definition of residual flutolanil for animal-based food commodities and MRLs established by the Codex Alimentarius, and will be useful for the regulatory monitoring of residual flutolanil and its metabolites in food products.     

Studies on the occurrence and formation of 2-(hydroxymethyl)-N-nitrosothiazolidine-4-carboxylic acid (HMNTCA) and 2-(hydroxymethyl)-N-nitrosothiazolidine (HMNTHZ) in various cured smoked meats,fish and cheese

Abstract : Because of the carcinogenic nature of many N-nitroso compounds, there is concern about their presence in foods. This paper presents some data on the levels of two non-volatile compounds (2-(hydroxymethyl)-N-nitrosothiazolidine-4-carboxylic acid (HMNTCA) and 2-(hydroxymethyl)-N-nitrosothiazolidine (HMNTHZ)) in various smoked foods such as 25 cured meats, eight smoked fish and seafoods, 15 smoked poultry products, and 17 smoked cheeses. All samples were negative for HMNTHZ, but 11 of the cured meats, six poultry products and two smoked fish contained HMNTCA at levels of 10–260 μg kg^?1. Upon frying, appreciable levels of HMNTHZ were formed in only one of 10 samples of cured meat products. The smoked cheeses were all negative for HMNTCA.     

Effect of ellagitannins,ellagic acid and volatile compounds from oak wood on the (+)‐catechin,procyanidin B1 and malvidin‐3‐glucoside content of model wines

Background and Aims: During ageing in oak barrels, wine undergoes changes because of the release of polyphenols and other molecules from wood. The aim of this study was to evaluate the influence of some oak wood‐derived volatile compounds, ellagic acid and oak wood extracts on the levels of (+)‐catechin, procyanidin B1 and malvidin‐3‐glucoside. Methods and Results: Phenolics and the oak wood derived volatile compounds studied were quantified by HPLC and by GC, respectively. Additionally, the new compounds formed in the solutions were characterised by their spectral properties. Ellagic acid and/or oak wood extracts slowed the decline in the levels of (+)‐catechin and procyanidin B1. In contrast, the decrease in malvidin‐3‐glucoside was more pronounced in the presence of ellagic acid and oak wood chip extracts. Furfural slowed (+)‐catechin degradation, while breakdown of malvidin‐3‐glucoside was slightly more pronounced in the presence of guaiacol, furfural, vanillin and eugenol. (+)‐Catechin, procyanidin B1 and malvidin‐3‐glucoside did not significantly affect the rate of the degradation of ellagitannins during the storage time studied. Finally, new HPLC peaks were detected in the solutions containing (+)‐catechin and ellagic acid, as well as with malvidin‐3‐glucoside with ellagic acid and oak wood extract. Conclusions: Malvidin 3‐glucoside and (+)‐catechin and procyanidin B1 presented distinct behaviours during time in the presence of volatile and non‐volatile compounds from oak wood. Significance of the Study: This work points out the importance of oak wood components in the degradation of anthocyanins and tannins, as well as the reactions that occur during the ageing of red wine.     

Effects of reaction mixture and other components on the determination of the equilibrium and rate constants of the hydration reactions of anthocyanins

The equilibrium and rate constants of the hydration and deprotonation reactions of anthocyanins show how their color intensity changes with pH. In the cases of several anthocyanins, the constants for each obtained by several methods are different. In an effort to resolve these discrepancies, we have examined the effects of several components of the pH-jump experiments on the values of the constants. Storage of the buffers to be used in pH-jump experiments in Pyrex or borosilicate glass bottles results in increasing Al³⁺ concentration in the buffers over several weeks. When these buffers are used, the anthocyanins with two OH groups on the B ring complex with the Al³⁺ which leads to major changes in their spectra, in the equilibrium position, and in the apparent first-order rate constant. Thus, constants determined on the same anthocyanin using the same buffers stored in glass bottles may be different at different times. During the reduction of the experimental data to the rate and equilibrium constants, two divergences from the expected behavior were found. In the calculation K_a + K_h for the anthocyanin acylated with 4-hydroxy-3,5-dimethoxycinnamic acid (6-O-(4-hydroxy-3,5-dimethoxycinnamoyl)-β-d-glucopyranosyl-(1 → 6)-[β-d-xylopyranosyl-(1 → 2)]-β-d-galactopyranosyl-(1 → O³)-cyanidin), the plotted points appear to fit two straight lines, intersecting at an equilibrium pH near pH 4. In the calculation which leads to the individual constants of both anthocyanins examined here, the points below an equilibrium pH of pH 4 curve upward from the line that describes the points from an equilibrium pH above 4. Differences in the composition of solutions used in pH-jump experiments examined here, include (1) the addition of phosphate to the acetate buffer, (2) the presence of 0.5 M NaCl, and (3) the solution of the anthocyanin in either 0.1 N HCl or 0.1 N HOAc. These changes gave differences that were statistically significant in some of the constants for each of the two anthocyanins examined. The constants were both qualitatively and quantitatively different.     

Mycosporine-like amino acid composition of the edible red alga, Palmaria palmata (dulse) harvested from the west and east coasts of Grand Manan Island,New Brunswick

The oxygen radical absorbance capacity (ORAC), antiproliferative activities and mycosporine-like amino acid (MAA) profiles of methanol extracts from two grades of dulse harvested from locations varying in UV-exposure (west vs east coasts of Grand Manan Island, NB) were determined in the present study. MAAs confirmed by LC/MS in both grades 1 (low-UV) and 2 (high-UV) dulse were palythine, shinorine, asterina-330, palythinol and porphyra-334; usujirene was present only in grade 2 dulse. ORAC values of grade 1 and 2 dulse extracts were 36.42 and 38.78 μmol Trolox/g extract. B16-F1 murine skin melanoma cell proliferation was inhibited (p < .05) by 68.5% and 91.9% by grade 1 and 2 dulse extracts at 6.0 mg/mL. The antiproliferative efficacy of grade 2 dulse was greater (p < .05) than grade 1 from 0.375 to 6.0 mg/mL. MAA differences between the grade 1 and 2 dulse extracts likely influenced the antiproliferative efficacies, despite the similar ORAC values.