咖啡豆的化学组分差异与感官品质的相关性分析

为了探讨咖啡中化学组分与感官品质之间的关系,通过测定7种不同产区咖啡豆的蛋白质、还原糖、绿原酸、葫芦巴碱和咖啡因含量以及咖啡液pH,分析这些组分含量的多少与感官品质之间的关系。经Pearson线性相关性检验,咖啡感官评分高低与咖啡因含量和葫芦巴碱含量的线性相关性具有显著性,均成负相关,相关系数分别为r=0.855和r=0.366。同时咖啡感官好的风味品质与咖啡因损失量(r=0.897)、葫芦巴碱损失量(r=0.848)、绿原酸损失量(r=0.933)、还原糖损失量(r=0.713)正相关性均为极显著,与蛋白质损失量的线性相关性不显著。另外,7种不同产区咖啡豆,不同烘焙程度和不同品种咖啡间pH的差异不大。      

Determination of Iriflophenone 3‐C‐β‐d‐Glucoside From Aquilaria spp. by an Indirect Competitive Enzyme‐linked Immunosorbent Assay Using a Specific Polyclonal Antibody

Polyclonal antibody against iriflophenone 3‐C‐β‐d ‐glucoside (IP3G), a major compound from the leaves of Aquilaria spp., was produced for the development of an enzyme‐linked immunosorbent assay (ELISA). The results showed that the antibodies were specific for IP3G. The produced antibody has low cross reactivity with iriflophenone 3,5‐C‐β‐d ‐diglucopyranoside (13%), genkwanin 5‐O‐β‐primeveroside (3.55%) and no cross reactivity found in other compounds. The range of ELISA assay extends from 100 to 1560 ng/mL with coefficient of variation (CV) 1.19% to 2.07% for intra‐assay and 3.76% to 7.15% for inter‐assay precision levels. The recovery rates of IP3G in the leaves of Aquilaria spp. were in the range of 96.0% to 99.0% with CV 4.50% to 5.32%. A correlation between ELISA and high‐performance liquid chromatography methods was obtained when analysis of IP3G in the plant samples (R² = 0.9321). These results suggest that the developed ELISA method can be applied to determine IP3G content with high specificity, rapidity, and simplicity. The developed immunosorbent assay in this study provides a useful tool for the analysis of IP3G in plant samples and products.     

Effect of sugarcane bagasse addition on physical,chemical, and sensory properties of oat flour and banana cake

The objective of this work was to evaluate the effect of sugarcane bagasse (SB) addition on chemical, physical, and sensory properties of the oat flour and banana cakes. The SB was added in the amount of 3 g and 6 g/100 g solids (BC3 and BC6) to obtain cakes considered “source of fiber” and “high in fiber content,” respectively. The addition of SB did not alter the chemical composition of the cakes except the dietary fiber which was higher in the BC6. The firmness of the cake increased with SB concentration, but this fact did not interfere in the sensorial acceptance of the product. The production of oat flour and banana cakes containing “high fiber content” with good sensorial acceptance was possible and demonstrated the reuse of an agro-industrial residue widely available the sugar and alcohol industry.     

Inhibitory activity towards human α‐amylase in wheat flour and gluten

Wheat α‐amylase inhibitors (AI) have been targeted as potential triggers of noncoeliac gluten or wheat sensitivity (NCGS). The aim of this study was to determine AI activity towards α‐amylase from human source in wheat cultivars. Contrary to barley, buckwheat, or oats, high level of AI activity was found in wheat and, to a lesser extent, rye. AI activity (mean IC₅₀ = 137 μg mL^?1) did not vary with respect to ancient or recently developed wheat cultivars. Vital wheat gluten had very high and heat‐stable AI activity (mean IC₅₀ = 23 μg mL^?1), higher than wheat starch (?10 000 μg mL^?1) or acarbose (40 μg mL^?1), a medication for the management of hyperglycaemia and potentially causing digestive disorders due to the accumulation of undigested carbohydrates in the intestine. Data suggest that eating raw wheat gluten, flour or dough could pose a health risk.     

Effect of pretreatments and drying methods on physico‐chemical,sensory characteristics and nutritional value of oyster mushroom

This study was aimed to evaluate the effect of pretreatments and drying methods on the chemical, physico‐chemical, sensory characteristics and nutritional value of oyster mushroom. Chemical analysis of oyster mushroom (OM) showed that the values content were increased by many times when calculated on dry weight basis. Nine treatments of dried mushroom powders (DMP) were prepared using three drying methods (hot air drying, vacuum drying, and sun drying). Also, three pretreatments of each method of drying were used (untreated, blanching by steaming without or with steeped in 0.5% citric acid solution for 30 min).The results and statistical analysis revealed that, sun dried oyster mushroom samples (without pretreatments) were found to be the best. The DMP samples resulting of the sun drying had a highest physico‐chemical properties, sensory evaluation scores, and contents of the mineral elements and amino acids as compared to other pretreatments and drying methods.

Practical applications

Fresh mushrooms have high water content, high enzymatic activity and hence are highly perishable. Thus, in this study nine treatments of dried mushroom powders (DMP) were prepared using three drying methods (hot air drying, vacuum drying and sun drying).Also, three pretreatments of each method of drying were used (untreated, blanching by steaming without or with steeped in citric acid).The DMP samples (untreated) resulting of the sun drying were better than other pretreatments and drying methods regarding quality attributes.     

Effect of oat β‐glucan and its oxidised derivative on the quality characteristics of sponge cake

The objective of this study was to investigate the characteristics of sponge cakes containing native oat β‐glucan (BG‐B) and its oxidised derivative with TEMPO (2, 2, 6, 6‐tetramethyl‐1‐piperidine oxoammonium ion) (Oxi‐B). BG‐B and Oxi‐B were substituted at 1% (w/w) into a formulation, and then the effects of BG‐B and Oxi‐B addition on the pasting properties of wheat flour and the physicochemical and textural properties of sponge cakes were determined. The pasting parameters of wheat flour were increased by BG‐B, whereas they were decreased in wheat flour with added Oxi‐B. The cake containing Oxi‐B had a lower volume, and a higher symmetry and uniformity than the BG‐B cake. The Oxi‐B cake exhibited smaller L* and b* values and a higher a* value than the control in crumb and crust colour. According to texture profile analysis, the BG‐B cake had increased hardness, chewiness and gumminess, whereas the Oxi‐B cake had decreased hardness.     

The effect of traditional production methods on microbial,physico‐chemical and sensory properties of ‘Slovenská bryndza’ Protected Geographical Indication cheese

Bryndza is a natural, white, mature and spreadable kind of cheese, and since 2008, it has been manufactured in specified mountainous areas of the Slovak Republic with Protected Geographical Indication. The aim of this work was to provide useful information about the microbial, physico‐chemical and sensory characteristics of bryndza, taking into consideration the variabilities related to the traditional methods of production technology of three bryndza cheese varieties. Statistically significant differences were observed in bryndza cheese production methods in chemical parameters of NaCl and malondialdehyde content (P < 0.05) and in the microbial presence of Enterococcus spp. (P < 0.001) and Staphylococcus spp. (P < 0.01).     

Variety and germination time effect on total β‐glucan,water‐insoluble β‐glucan,water‐soluble β‐glucan components and β‐glucanase levels in improved sorghum varieties SK5912, KSV8 and ICSV400 before and after malting and their relationships to wort viscosity

The effects of variety and germination time on β‐glucan components – total β‐glucan (TBG), water insoluble β‐glucan (WIBG) and water soluble β‐glucan (WSBG) and β‐glucanase (BG) levels – before and after malting in improved sorghum varieties SK5912, KSV8 and ICSV400 and their relationships to wort specific viscosity (SV) were studied. This study was part of efforts to aid local malting and brewing industries in the application of sorghum varieties that are abundantly available to reduce costs. At the fifth day of germination, variety ICSV400 had the lowest TBG, WIBG and WSBG levels in its raw and malt samples. Variety SK5912 had the highest TBG, WIBG and WSBG levels in its raw samples, while variety KSV8 had the highest levels of TBG, WIBG and WSBG in its malt samples. Similarly, variety ICSV400 malts developed the highest BG levels, while the KSV8 malts gave the lowest level. The effect of variety, germination time and variety × germination time interaction was significant (p < 0.05) on the TBG, WIBG and BG levels and was not significant on the WSBG levels. Weak and significant correlation of TBG levels with SV (0.25, p < 0.05 for SK5912; 0.24, p < 0.05 for KSV8; and 0.31, p < 0.05 for ICSV400) was observed in all the samples, suggesting that the low β‐glucan levels may not be primarily and solely responsible for any viscosity impediments associated with sorghum worts during run‐off. With improvement in the effective utilization of sorghum, ICSV400 appeared the most suitable variety for malting and brewing in Nigeria.Copyright © 2016 The Institute of Brewing & Distilling     

Effect of gamma irradiation on the physico‐chemical and sensory properties of raw shelled peanuts (Arachis hypogaea L.) and pistachio nuts (Pistacia vera L.)

Backround The present study evaluated the quality of raw peanuts and pistachio nuts as a function of irradiation dose in order to determine dose levels causing minimal undesirable changes to these products. Physico‐chemical (colour, peroxide value, hexanal content, fatty acid composition, volatile compounds) and sensory (colour, texture, odour, taste) properties of raw peanuts and pistachio nuts were determined after irradiation at doses up to 7 kGy. Results Results showed an eight‐ and seven‐fold increase in peroxide value and a twelve and five‐fold increase in hexanal content after irradiation at a dose of 7 kGy for peanuts and pistachio nuts, respectively. An increase was also observed in saturated fatty acids (20.51–28.28% and 15.24–24.87%) with a parallel decrease in unsaturated fatty acids (79.49–71.72% and 84.76–75.13%) for peanuts and pistachio nuts, respectively. Likewise, volatile compounds such as aldehydes, alkanes, ketones and alcohols comprising secondary oxidation products of peanut and pistachio nut lipids increased after irradiation. Pistachio nut colour parameter a* and to a lesser extent parameters, L* and b* decreased after irradiation leading to a slight but noticeable darkening in product colour while colour parameter L*, b* and a* of raw peanut remained unchanged by irradiation up to 7 kGy. Conclusion Based on sensory evaluation, peanuts and pistachio nuts become unacceptable for consumption when irradiated at doses higher than 3 kGy. Copyright © 2009 Society of Chemical Industry     

Vitamin E levels,thiobarbituric acid test and sensory evaluation of breast muscles from broilers fed α‐tocopheryl acetate‐ and β‐carotene‐supplemented diets

The objective of this study was to investigate the effect of dietary α‐tocopheryl acetate and β‐carotene supplementation on lipid oxidation of breast meat from broilers fed lard as the fat source. Supplementation of broilers with 100 mg kg^?1 α‐tocopheryl acetate increased the vitamin E levels in raw breast samples significantly (p < 0.05), whereas the presence of 1.5 mg kg^?1 dietary β‐carotene tended to decrease vitamin E deposition. The presence of vitamin E delayed lipid oxidation significantly, but thiobarbituric acid values of samples from broilers fed the β‐carotene‐supplemented diet did not differ from those of control samples. Vitamin E reduced sensory meat rancidity, whilst vitamin E, β‐carotene and their combination modified meat texture. The results show the effectiveness of dietary α‐tocopheryl acetate supplementation in protecting broiler meat against lipid oxidation. Copyright © 2004 Society of Chemical Industry     

KC-2A膨胀介质对烟丝化学成分和感官品质的影响

研究了新型膨胀介质(KC -2A)在使用不同膨胀方法(微波、蒸汽)时,对烟草化学成分、感官品质的影响,并对膨胀前后烟丝化学成分、烟气化学成分的变化进行了测定,对膨胀前后的感官品质进行了评价.结果表明:新型环保介质烟丝膨胀工艺的膨胀烟丝各项理化指标与目前国内膨胀烟丝指标相当,其中微波膨胀的烟丝香气略好.     

Omega‐3 fatty acid‐fortified butter: Preparation and characterisation of textural,sensory, thermal and physico‐chemical properties

The influence of adding flaxseed oil (2.9–5.1%) and flaxseed–whey protein concentrate (WPC) emulsion (4.8–8.6%) to cream as an omega‐3 fatty acid source was evaluated on the thermal, sensory and physico‐chemical properties of the developed butter. Pulsed nuclear magnetic resonance analysis revealed lower saturated fat content in the fortified butter than control butter. Differential scanning calorimetry exotherms and endotherms also corroborated these findings. Fortified butter prepared with 6.8% flaxseed oil–WPC emulsion had 3.7 times more alpha‐linolenic acid content than control and provided nearly 25% of the recommended dietary allowance in one serving. The developed butter exhibited improved spreadability.     

The effects of refined barley β‐glucan on the physico‐structural properties of low‐fat dairy products: curd yield,microstructure, texture and rheology

The beneficial role of dietary fibre in human nutrition has lead to a growing demand for incorporation of novel fibres, particularly barley β‐glucans, into foods. Barley β‐glucans are regarded as dietary fibre ingredients that are partially soluble in water. The aim of the present work was to investigate the possibility of using barley β‐glucan in milk systems in relation to the coagulation properties of milk containing β‐glucan, and to the rheology, texture and microstructure of fresh curds. The rate of coagulation and optimum coagulum cutting time were evaluated using rheological measurements. Results show that coagulation/gelation time of the milk can be reduced significantly with the incorporation of β‐glucan; curd yield increased and the viscoelastic properties of the curd were altered with β‐glucan additions. The relationships between curd rheological behaviour and its microstructure are discussed in relation to use of novel hydrocolloids in dairy processing. The results suggest that barley β‐glucan has the potential to be used as a fat replacer in low‐fat dairy systems. Copyright © 2004 Society of Chemical Industry