A mathematical model for colour loss in paprikas containing differing proportions of seed

In this paper a general kinetic model for predicting the colour of paprikas with differing proportions of seed as a function of the storage conditions is developed. We apply this model to study the effect of time and storage conditions on colour loss in paprikas made from the same pepper variety, Ocal, but with differing proportions of seed. The agreement between the experimental colour data for this paprika and the results predicted by the mathematical model is very good. Both the model and the experimental data show that the rate of colour loss decreases with increasing proportion of seed, and after a determined inversion time the samples with the lowest initial colour values actually show the highest values. Likewise, the experimental data show that for a given proportion of seed the colour loss decreases as the storage relative humidity increases. © 2000 Society of Chemical Industry     

Critical assessment of antioxidant‐related parameters of honey

In this study, several antioxidant‐related parameters were researched on 56 Spanish honeys, setting up and optimising some assays. Melissopalynology and colour (L*, a*, b*) were determined. Solid‐phase extraction (SPE) was used to obtain honeys’ phenolic extracts. Total phenolics, total flavonoids and trolox equivalent antioxidant capacity (TEAC) were determined in both honeys and extracts. It was verified that total flavonoids determination in neutral media must be carried out on extracts instead of on honeys, because of sugars’ interferences; likewise, extracts’ colours must be corrected in this assay. The endpoint for honeys’ trolox equivalent antioxidant capacity (TEAC) was researched. Significant linear relationships were found between TEAC values of honeys and honeys’ phenolic extracts, as well as between the results of TEAC measured at different times. Therefore, it would be possible to reliably calculate TEAC at 60 min (endpoint), measuring the absorbance at 6 min, thus saving analysis time and reducing costs.     

Influence of storage conditions on pigment degradation in paprikas from different greenhouse pepper cultivars

A comparative study was made of the pigments and kinetics of pigment degradation in paprika from Ocal, Datler, Belrubí and L T Datler varieties of pepper cultivated in greenhouse conditions during storage in darkness and at different temperatures and degrees of humidity. Differences were established after fitting the experiment data to a first- or second-order kinetic model. The pigment degradation rate constants and half-lives were obtained for each variety and each storage condition. As expected, the speed of pigment degradation increased for all the paprika types at higher storage temperatures and decreased as relative humidity rose. The data obtained allowed the determination of the parameters involved in the respective Arrhenius equations which equate the pigment degradation rate constant (supposed first or second order) with absolute temperature in cases of zero humidity. Significant differences with respect to degradation rate and pigment content were found between the cultivars in most of the storage conditions assayed. © 1998 Society of Chemical Industry.     

The Effect of Hydroxycinnamic Acids and Volatile Phenols on Beer Quality

To the consumer, beer should be an agreeable beverage of attractive colour, clarity, pleasing flavour and should carry no toxic substances. One of the major constituents of barley is phenolic acids and their direct effect on the quality of beer is still a mystery. The aim of the study therefore was to investigate the relationship between phenolic acids during mashing at different temperatures and the quality of the beer. The mash regime and liquor to malt ratios were optimised and the carbohydrates obtained were analysed at 3.5 L of water per kg of malt and a total mash time of 105 min. Carbohydrate and phenolic acid analyses were performed by HPLC coupled with a UV‐vis detector. The three different malts used had a phenolic acid content of 33.25 μg/mL, 25.44 μg/mL and 19.98 μg/mL for malt A, B and C, respectively. The plot of 1/T versus Ln(t) gave a negative slope with activation energy (E_a) = 209 KJ/mol, rate constant (k) = 4.6 × 10^?4 mg/L min, which are comparable to similar data reported in the literature. The kinetics studies showed that the optimised mashing temperature of 90°C was adequate to form 4‐vinylguaiacol by thermal decarboxylation from the hydroxycinnamic acids. This study has shown that there is no direct correlation between phenolic acids and oxidative flavour stability of beer while the corresponding volatile phenols may affect beer flavour.     

Quality assessment of dehydrated red bell pepper using tempering drying cycles

Quality assessment of red bell pepper dices preserved through batch dehydration introducing tempering cycles were performed in this work. The parameters considered were: the percentages of ascorbic acid and final antioxidant activity retention, as well as the influence of calcium chloride on diffusivity and colour values. Although, a similar final moisture content was reached through different red bell pepper dehydration processes, but the one with tempering cycles had better qualities than those without tempering. Ascorbic acid and final antioxidant activity retention showed higher values and so were colour intensities compared to control samples in all cases. In respect to the effective diffusivity coefficients, there was an increment as the calcium chloride concentration increased. As of the treatments with tempering cycles, the best scheme was 15 min drying time and 30 min tempering time at 60 °C.     

大豆磷脂产品质量控制——大豆磷脂的颜色和风味

综述了大豆磷脂颜色的来源 ,大豆磷脂褐色物质的生成。介绍了磷脂中产生各种气味的物质和油脂加工过程中混合油吸附过滤和脱色、水化脱胶工艺条件、脱胶剂对大豆磷脂颜色的影响。对磷脂制备工艺中常采用的过氧化苯甲酰、过氧化氢化学脱色法以及浓缩磷脂的白土脱色、浓缩磷脂活性炭吸附脱色作了介绍     

Quality and antioxidant properties of bread containing turmeric (Curcuma longa L.) cultivated in South Korea

Turmeric (Curcuma longa L.) powder was used to substitute 0%, 2%, 4%, 6% and 8% of wheat flour for making turmeric wheat breads. Proximate composition, physical quality, functional components (curcumin and total phenols) and antioxidant properties of breads containing turmeric were analysed and compared with those of wheat bread. Hardness, crumb colour a and b values, curcumin content and total phenolic contents of breads significantly increased with the addition of turmeric powder. Water activity, specific volume and crumb colour L value of breads decreased with the addition of turmeric powder. Breads containing turmeric powder also showed good antioxidant activity as tested by the β-carotene-linoleate bleaching assay. A 4% substitution of wheat flour with turmeric powder showed acceptable sensory scores which were comparable to wheat bread. Breads containing turmeric powder can thus be developed as a health-promoting functional food.     

Enrichment of fresh pasta with antioxidant extracts obtained from artichoke canning by‐products by ultrasound‐assisted technology and quality characterisation of the end product

This work is aimed at: (i) analysing the extracts obtained from canning by‐products of three artichoke cultivars (Opal, Capriccio and Catanese) for antioxidant parameters; (ii) comparing UHPLC‐ESI‐MS/MS profile, colour, textural properties and cooking performance of fresh pasta enriched of the most antioxidant extract, with control pasta. The concentrated Catanese cv. extracts showed the highest antioxidant activity (1662 μmol Trolox equivalents L^?1) and the highest levels of luteolin‐7‐O‐rutinoside, luteolin‐7‐O‐glucoside and apigenin‐7‐O‐rutinoside compared to other cultivars. Fresh pasta enriched of Catanese extract showed higher (P < 0.05) phenolic compounds and antioxidant activity (500 mg gallic acid kg^?1 and 1324 μmol Trolox kg^?1, respectively) than control pasta (306 mg gallic acid kg^?1 and 886 μmol Trolox kg^?1, respectively). The extract increased (P < 0.05) pasta brownness (from 19.93 to 23.34), and decreased yellowness (from 27.11 to 23.09), but did not alter textural and cooking parameters. So, pasta was a good vehicle to increase the antioxidant dietary intake.     

Phytochemicals content,antioxidant and hypoglycaemic activities of commercial nutmeg mace (Myristica fragrans L.) and pimento (Pimenta dioica (L.) Merr.)

Commercially dried powder of nutmeg mace (Myristica fragrans) and pimento (Pimenta dioica) spices was investigated for their high performance liquid chromatography phenolic profile and their antioxidant and hypoglycaemic properties by α‐amylase and α‐glucosidase inhibition tests. Generally, mace showed the most promising activity. An interesting protection of lipid peroxidation with an IC₅₀ value of 7.7 μg mL^?1 was found. A significant result was also obtained in ferric reducing ability power assay if compared to the positive control butylated hydroxytoluene (IC₅₀ value of 68.7 μg mL^?1 vs. 63.2 μg mL^?1, respectively). Mace also exhibited the highest carbohydrate‐hydrolysing enzyme inhibitory activity with IC₅₀ values of 62.1 and 75.7 μg mL^?1 against α‐amylase and α‐glucosidase, respectively. Overall, these results support the use of these spices not only as flavouring agent but also as food preservative and functional ingredients.     

Deposition of Carotenoids in Eggs from Hens Fed Diets Containing Saponified and Unsaponified Oleoresin Paprika

Deposition of carotenoids in saponified paprika (SP) and unsaponified oleoresin paprika (OP) in egg yolks as well as the dietary level for desired pigmentation were evaluated. Sixty-four hens on a carotenoid-depletion diet were divided into two replicated groups of each of eight dietary treatments containing from 0 to 16 mg paprika carotenoids per kg feed. Colour and the carotenoid content of egg yolk increased linearly ( P< 0·01) with the amounts of paprika carotenoids in the diets. The colours of egg yolks from hens fed similar concentra-tions of OP or SP were not significantly different ( P< 0·01). A low dose (4 mg kg⁻¹) of OP or SP provided yolk colour equivalent to the colour of eggs in supermarkets. High-performance liquid chromatographic analyses showed that carotenoids deposited in the yolk are in the free alcohol form, regardless of the form of carotenoids in the diet. Capsanthin, the predominant carotenoid in paprika, was deposited in egg yolk less efficiently than zeaxanthin and lutein.     

Effect of adding natural antioxidants on colour stability of paprika

We analysed the effect of adding rosemary and tocopherol extracts, two natural antioxidants, on the colour stability of paprika stored at different temperatures and degrees of relative humidity. Any possible synergistic effect of their joint use was also investigated. The experimental data concerning colour loss, as determined by the ASTA 20.1 method, fitted first‐ and second‐order kinetics, which provided the rate constants of colour loss and half‐lives of the samples. The first finding concerned the antagonistic effect between storage temperature and humidity. The antioxidants had a clear protective effect on colour stability in all the conditions assayed, the superior effect of one or the other depending on the storage temperature. A synergistic effect of both antioxidants at temperatures between 25 and 40 °C was evident. The experimental data referring to colour loss for most of the storage conditions assayed fitted second‐order kinetics best. © 2002 Society of Chemical Industry     

Effect of ascorbic acid addition to peppers on paprika quality

The use of ascorbic acid addition to foods to protect pigments from oxidation has been widely applied. Control or ascorbic acid-added paprika peppers were processed in a similar way as for paprika manufacture. During the process, lipoxygenase activity, total colour, red/yellow pigment ratio and ascorbic acid levels were measured. In general, an increase of total colour and red pigments was observed in ascorbic acid-treated samples. The lipoxygenase activity was depressed in ascorbic acid-treated fruits on the first day of processing. However, the activity was increased again, at second day, when the ascorbic acid was oxidised, showing a close relationship between enzyme activity and the antioxidant. After the process, ascorbic acid was also added to half of the paprika from control peppers and its quality and stability of the pigments against light or heat was compared to the paprika from ascorbic acid-added peppers. At the end of the treatment a better quality was observed in paprika obtained from the ascorbic acid-added peppers. ©1997 SCI     

Contribution of objective and subjective attributes to the variation in the whiteness and brightness of commercial mohair sale lots

Colour properties are measured prior to the sale of merino wool as they are of commercial importance when greasy wool is sold and when wool is dyed. With the paucity of knowledge of the colour properties of commercial mohair, this study aimed to identify and quantify the factors affecting the brightness (Y) and yellowness (Y-Z) values of commercial lots of Australian mohair. The research database comprised 520 sale lots (>500,000 kg mohair), which had tristimulus tests, and was sold during the period 2001–2009. Mohair was subjectively classed and sale lots objectively tested using international standard methods for mean fibre diameter (MFD, μm), fibre diameter coefficient of variation (%), International Wool Testing Organization (IWTO) clean wool base (IWTO yield, %w/w), vegetable matter (VM, %w/w) and the tristimulus values X, Y and Z (T units). The tristimulus values of Australian mohair were affected by the objective measurements of MFD, VM%, the subjective classing of stain, cotting, kemp and length and by the year and selling season. Variation in Y was more easily predicted with 90.5% of variance explained by the best model compared with variation in Y-Z, where the best model explained 51.6% of the total variance. Visually assessed properties of the mohair were very important in separating mohair of different Y properties, accounting for almost 80% of the total variance, but were far less important in accounting for the variance in Y-Z, accounting for about 9–10% of the total variance. The most important effects on the Y of mohair were associated with subjectively determined fault categories determined before the sale of mohair. In particular, stain fault explained about two-thirds of the variance in brightness of mohair sale lots. Stained mohair had much lower brightness than mohair free of stain but stain fault explained very little of the variation in yellowness of mohair sale lots. The extent of the differences in tristimulus values between seasons and years were not large for Y but were more important for yellowness (Y-Z), and these effects are likely to be of commercial importance. Generally, brightness decreased and yellowness increased as MFD increased up to about 30 μm. Both cotting and kemp fault were associated with reduced brightness and increased yellowness. The effects of VM% on tristimulus values were small. IWTO yield was associated with changes in tristimulus values, but in the best model, IWTO yield was not a significant determinant. This study indicates that commercial Australian fleece (nonfaulted) mohair was essentially white. Faulted mohair on the other hand exhibited poorer colour characteristics. The mohair subjectively identified as stained prior to sale comprised all the mohair which would be regarded as not white, and this investigation indicates that the effect of staining is on the brightness of mohair rather than the Y-Z measurement. Unlike the situation with merino wool, there was little relationship between the naturally occurring contaminants, as measured by the IWTO washing yield, and either Y or Y-Z.     

光质对番茄果实品质及挥发性物质的影响

以‘金棚朝冠’为实验材料,研究植物工厂内不同比例红蓝光（R、2R1B、1R1B、1R2B和B）（白光为对照组）处理对番茄单果质量、主要品质性状及挥发性物质的影响。结果表明：2R1B（红光∶蓝光＝2∶1）处理可以显著提高番茄单果质量以及可溶性蛋白、抗坏血酸和番茄红素的含量,R（红光）处理条件下可溶性固形物含量、可滴定酸质量分数和糖酸比均显著高于白光对照（P＜0.05）。利用顶空固相微萃取结合气相色谱-质谱联用对番茄果实的挥发性物质进行测定,发现与其他比例的红蓝光处理相比较,R和2R1B提高了挥发性物质的总量。本研究结果为利用不同光质提高番茄果实品质和风味提供了理论依据。     

Evaluation of volatile compounds and antioxidant capacity of some commercial rums from Dominican republic

Some Dominican ‘heavy’ rums, of a single brand, available commercially and labelled as 8, 15, 18, 21 and 25 year‐old have been evaluated and compared. Headspace solid‐phase microextraction (HS‐SPME) coupled to gas chromatography–mass spectrometry (GC–MS) was used to analyse volatile compounds and crocin kinetic competition test to evaluate their antioxidant capacity. The alcohols and esters profiles of rums labelled as 21‐ and 25 year‐old were similar. The alcohols and fatty acids profiles of rums labelled as 15 and 18 year‐old were similar. The esters profile of rums labelled as 8 and 15 year‐old was similar. Significant differences were found for aldehydes and volatile phenols between all the rum samples. The antioxidant capacity resulted significantly higher in the older rums (21 and 25 year‐old) than in the younger ones (8, 15 and 18 year‐old).     

Relationships between colour parameters,phenolic content and sensory changes of processed blueberry,elderberry and blackcurrant commercial juices

There is an increased interest in the consumption of fruits containing high phenolic concentrations such as berry fruits. Attractive colour of berries plays a vital role for consumer acceptance. The aim of this work was to evaluate colour parameters (a*, b*, L*), phenolic content and sensory changes of blueberry, elderberry and blackcurrant (BC) pasteurised commercial juices during accelerate storage. Initial phenolic concentration was 3.21, 10.06, 10.72 g GAE L^?1 for blueberry, elderberry and BC, respectively. Moreover, phenolic concentration of all juices decreased by approximately 40% throughout the first 30 days. Blueberry exhibited a substantial decrease in a* (40%) in the first 30 days, while elderberry presented a gradual decrease and BC only presented a slight decrease (7%) at the end of storage. Colour preferences decreased when storage time increased. However, when consumers were informed that ‘the juices are a rich source of phenolics, which contribute to reducing risk of suffering chronic diseases’, a high level of purchase intention was obtained.     

How meaningful is the assessment of antioxidant activities in microheterogeneous media?

Ignoring environmental factors in microheterogeneous solutions of antioxidants may lead to significant distortions and inconsistencies in the assessment of their activities. The importance of the hydrophobicity of the antioxidants and of the assaying radicals in such media is illustrated by comparing the reactivities of three phenols of different hydrophobicity, 3,5-di-t-butyl-4-hydroxytoluene (BHT), 6-hydroxy-2,5,7,8-tetramethylchromane-2-carboxylic acid (Trolox) and Quercetin compared to radicals TEMPO (2,2,6,6-tetramethylpiperidine-1-oxyl) and 4-amino-TEMPO in micellar solutions of variable acidity of reduced Triton-X 100. The relative reactivities of these radicals, measured by EPR spectroscopy, indicated that the hydrophobicity of the involved species is a factor that should always be considered in the evaluation of antioxidants, with the risk of arriving at wrong conclusions regarding their activities.     

The effect of different paprika types on the ripening process and quality of dry sausages

The main objective of the study was to evaluate the effects of large amounts of paprika and different amounts of hot paprika on the ripening process of dry sausage. The sausages, called ‘chorizo’ were evaluated for changes in texture, colour and physico‐chemical parameters, including rancidity. The results show that when either paprika contents or concentrations of hot paprika were increased, compared with a control, the ripening process of dry sausages was accelerated, probably by the promotion of lactic acid bacteria growth, which, in turn, lead to a fast drop in pH and water activity. These effects cause a rapid development of texture when compared with a suitable control, with an optimal hardness being reached in less time. These products have greater colour intensity, which remains more stable, together with lower malonaldehyde contents than controls. It was shown that paprika, especially the hot variety, exerts a protective effect against rancidity.     

虾青素微球对酸奶品质与风味的影响

以虾青素微球、鲜牛乳为原料,制备虾青素微球酸奶,评价虾青素微球对酸奶的乳酸菌活菌数、质构、感官评分、贮藏期虾青素稳定性的影响,并采用顶空气相色谱-离子迁移谱对酸奶挥发性有机物进行分析.结果 表明:虾青素微球对乳酸菌活菌数有积极作用,对酸奶的质构无显著性影响(P＞0.05);当虾青素添加量为6 mg/100 g时,虾青素...     

市售蚝油产品品质的评价

在对滋味、质构、色泽和常规理化指标进行测定的基础上,本研究采用多元统计学方法,对市售蚝油的产品品质进行了分析。研究表明市售蚝油样品在基本味、回味、红绿度和黄蓝度上的差异较大,而在各质构指标和明亮度上的差异较小。通过围绕中心点的分割算法分析发现市售蚝油样品根据其品质特征可划分为3个聚类,不同聚类间的蚝油样品其酸味、涩味和后味A(涩的回味)存在显著差异(p<0.05)。