Comparison of colorimetric and spectrophotometric methods for colour determination in pasta

 Product colour is one of the most important criteria for determining pasta quality. For pasta produced without eggs, pasta colour will depend mostly on the content of the yellow pigment in flour. Analyses were done with 12 samples of hand-made pasta without eggs. The yellow pigment content was determined by the standard spectrophotometric method, while the pasta colour (fresh shaped and dry milled pasta) was measured using the Minolta CR-300 colorimeter. The results obtained show that there is a correlation between spectrophotometric determination of the yellow pigment content and the results of colorimetric measurement. The correlation coefficient between the colorimetric results of dry milled pasta and the yellow pigment content is higher than that between the colorimetric results of fresh shaped pasta and the yellow pigment content.     

Optimising process for making pasta from maize in admixture with durum wheat

Processing conditions for making pasta from blends of maize (Zea mays L) flour and durum wheat (Triticum durum Desf) semolina (ratio 66:33 w) were studied. The maize mill stream characteristics determined the quality of the maize pasta; flours with low lipid content and very fine granulometry produced pasta with good colour characteristics and high cooking quality (with especially good surface conditions). The use of white maize varieties was preferred; they produced pasta which, after heat treatment, had colour indices close to those of durum wheat pasta. Extrusion conditions affected the colour characteristics and cooking quality of the pasta. The cooking qualities of macaroni products were better than those of spaghetti. In all cases, heat treatment (90°C for 2 h) improved the cooking quality of the pasta: it reduced cooking losses but did not alter the surface condition and viscoelasticity index.     

Mechanism of Browning in Fresh Highbush Blueberry Fruit (Vaccinium corymbosum L). Role of Blueberry Polyphenol Oxidase,Chlorogenic Acid and Anthocyanins

Browning reactions which occurred after crushing fresh blueberries (Vaccinium corymbosum L) were followed by determination of chlorogenic acid colour density, polymer colour and the level of polymers. A polyphenol oxidase (PPO) activity plays a dominant role in enzymatic browning. Peroxidase (POD) does not contribute to brown colour formation. The loss of 29% of the colour in a model system containing PPO and blueberry anthocyanins indicated that PPO could act directly on these pigments. However, the rate of anthocyanin degradation was stimulated by the addition of chlorogenic acid. © 1997 SCI.     

Effect of different shapes on the quality, microstructure, sensory and nutritional characteristics of yellow pea flour incorporated pasta

The objective of present study was to understand the interaction of yellow pea flour and T. durum semolina in pasta processing and also the influence of different shapes of pasta on product quality and nutritional profiles. Different levels of substitution—10, 20 and 30 % of yellow pea flour in noodles was carried out. Results indicated that noodles with 20 % yellow pea flour had favorable sensory attributes, protein content, good texture, yellowness values, reduction in the glucose release and increased protein digestibility. Shell pasta (Conchiglie), noodle and vermicelli were extruded with the optimized 20 % pea flour for comparison. Proximate composition results showed an increase in protein content for all the samples (~2.5 %) compared to control, which is also evident in the SDS-PAGE. Noodles retained yellowness, high sensory scores and good protein digestibility. Conchiglie pasta had the lowest cooking loss (4.21 %) and a good firmness. Amylose leach out of pasta samples did not vary significantly. Scanning electron microscopy studies revealed that noodles and vermicelli had disrupted network of starch and protein while Conchiglie had intact network. Considering nutritional point of view, vermicelli and Conchiglie pasta shapes had good effects. Both reduced the glucose release and also there was slower starch digestibility.     

超高静压对非浓缩还原杨梅果汁中氧化酶的钝化作用

该研究以非浓缩还原（not from concentrate,NFC）杨梅果汁为研究对象,研究不同超高静压（high hydrostatic pressure,HHP）处理（300~600 MPa/0~30 min）对NFC杨梅汁中多酚氧化酶（polyphenol oxidase,PPO）和过氧化物酶（peroxidase,POD）的影响。对比传统高温灭酶,拟合建立HHP压力与酶活性的一级动力学回归方程,分析得到相关参数（压力脉冲效应PE、压力脉冲数值ND、等效破坏值Dp及酶的失活速率K）。结果表明,较高压力（400~600 MPa）对PPO与POD均起到钝化效果,其中600 MPa/10 min能钝化90%的PPO活性,600 MPa/20 min钝化80%的POD活性。600 MPa/30 min条件下,重复加压不能明显加强钝化效果。将PPO和PPO活性与压力进行一级动力学拟合,得到相应线性回归方程（R2>0.8）。随着压力从300 MPa升高到600 MPa,PPO的K值从3.03×10-2升高到12.12×10-2,POD的K值从1.23×10-3上升到7.67×10-3。600 MPa条件下,PPO和POD的ND分别为1.04和1.59,Dp值都为19。同时,压力和保压时间及其相互作用对PPO和POD活性的影响均有极高的显著性（p<0.001）。因此,HHP对杨梅果汁中关键的氧化酶能起到较好的钝化作用,能够为NFC杨梅汁加工技术的应用提供科学依据。     

Quality of spaghetti pasta containing Mexican common bean flour (Phaseolus vulgaris L.)

The objective of this research was to study the effect of the addition of common bean flour to semolina on the cooking quality and total phenolic content of pasta. Pasta was obtained at three temperatures (60, 70 and 80 °C) and two levels of added common bean flour (15% and 30%); plain pasta (100% semolina) was used as control. Moisture, optimal cooking time, cooking loss, water absorption capacity, colour change, firmness and total phenolic and furosine contents were measured. The cooking time and water absorption were diminished in spaghetti pasta with added common bean flour; cooking loss increased and firmness decreased as a function of the bean flour percentage. A linear relationship between colour change and common bean flour content in pasta was found. Increases of furosine and phenolic contents in pasta with the addition of bean flour were observed.     

Changes in selected quality characteristics of minimally processed carambola (Averrhoa carambola L.) when treated with ascorbic acid

‘B 10’ carambola of ripening stage (RS) 3 and 4 were minimally processed (MP) and then dipped in 0, 15 and 30 mg L^?1 ascorbic acid (AA). The 1‐cm‐thick slices were then dried, packed into cling‐wrapped‐foam tray and stored at 7 °C for 0, 3 and 5 days. Skin colour (L*, C* and h°), flesh firmness, soluble solids concentration, vitamin C content, titratable acidity, pH, degree of browning, polyphenoloxidase (PPO) activity and sensory attributes of MP carambola treated with AA were determined. AA treatment had significant effect in decreasing cut surface browning degree but no significant effect on all the selected quality characteristics of the MP carambola. In the sensory evaluation, flesh colour, sweetness, flavour and overall taste were significantly affected by AA treatment especially at 15 mg L^?1. The RS of fruit significantly affected skin colour (C* and h°), pH and sensory attributes of colour and flavour of the MP carambola. As storage day (SD) progressed, skin colour (C* and h°), flesh firmness and vitamin C content, cut surface browning, PPO activity and all the sensory attributes of MP carambola decreased significantly. Flesh firmness of the MP carambola was affected by the interaction between AA × SD. Sensory attributes of MP carambola were affected significantly by AA × RS. All the sensory attributes of MP carambola positively correlated to each other but negatively correlated with browning degree. PPO activity positively correlated with browning degree. Copyright © 2007 Society of Chemical Industry     

Thermal inactivation kinetics parameters of browning enzymes in starfruit (Averrhoa carambola L.) juice

This study aimed to evaluate the thermal inactivation kinetics of polyphenol oxidase (PPO) and peroxidase (POD) in starfruit juice. It followed the Malaysia Food Regulations 1985 and CODEX STAN 247-2005. Glucose, fructose and sucrose were the main sugars in starfruit juice. The total soluble solids, pH, titratable acidity, and total phenolics content of the starfruit juice produced were 8.13 ± 0.25 °Brix, 3.80 ± 0.05, 0.43% ± 0.02% malic acid, and 93.67 ± 4.96 mg GAEL⁻¹, respectively. Thermal inactivation kinetics of PPO and POD followed the first-order kinetic model. The decimal reduction time at 83.6 °C (D_83.6) of PPO and POD was 198.48 and 98.4 s, respectively, while the thermal resistance constant (z value) of PPO and POD was 12.8 and 5.4 °C, respectively. In conclusion, PPO might be a suitable signal for thermal processing on starfruit juice since it has higher heat resistance than POD.     

Technological properties and non-enzymatic browning of white lupin protein enriched spaghetti

Spaghetti was prepared by replacing semolina with different amounts of lupin protein, in order to increase the protein content. A detailed investigation of the rheological properties of the dough and the cooking quality of pasta was performed in comparison to standard semolina spaghetti. Moreover, the effect of the addition of lupin protein on non-enzymatic browning was evaluated by measuring ε-furoylmethyllysine (furosine) and 5-hydroxymethyl-2-furancarboxaldehyde (HMF), which are considered useful indices of semolina quality and pasta processing conditions. Dried spaghetti fortified with 5% of lupin protein isolate has a colour and rheological features comparable with the semolina sample and also the behaviour during cooking results to be satisfactory. As far as the thermal damage is concerned, the furosine values of fortified spaghetti differ only marginally from standard pasta and the percentage lysine loss is quite small (ranging from 12.1% to 15.7%).     

Effect of Pleurotus eryngii Mushroom β‐Glucan on Quality Characteristics of Common Wheat Pasta

The objective of this study was to evaluate the effect of β‐glucan‐rich fractions (BGRFs) from Pleurotus eryngii mushroom powder on the quality, textural properties, and sensory evaluation of common wheat pasta. Pasta was prepared from semolina flour and common wheat flour by replacing common wheat flour at 2%, 4%, and 6% with BGRFs. Semolina flour showed significantly higher viscosities than common wheat flour samples. However, all viscosities, except the breakdown viscosity, were reduced with increasing percentages of BGRFs. Replacement of the common wheat flour with BGRFs resulted in a reddish brown colored pasta with a lower L* value and a higher a* value. The common wheat pastas containing up to 4% BGRFs were not significantly different from semolina pasta with regard to cooking loss. Addition of up to 2% BGRFs had no significant impact on swelling index and water absorption. The addition of BGRFs in common wheat flour had a positive effect on the quality of common wheat pasta and resulted in hardness values similar to those of semolina pasta. In a sensory evaluation, cooked pasta with 2% BGRFs had the highest overall acceptability score. In summary, the results showed that common wheat flour containing 4% BGRFs could be used to produce pasta with an improved quality and texture properties similar to semolina pasta.     

Germinated Cajanus cajan seeds as ingredients in pasta products: Chemical,biological and sensory evaluation

Pigeon peas (Cajanus cajan) seeds were germinated for 4 days at 20 °C in darkness in order to improve the nutritional quality of seeds. Germination brought about a sharp reduction of α-galactosides, phytic acid and trypsin inhibitor activity (83%, 61% and 36%, respectively) and an increment of vitamin B₂ (145%), vitamin C (from negligible amounts to 14 mg/100 g d.m.), vitamin E (108%) and total antioxidant capacity (28%). These flours were used as ingredients to produce pasta products in a proportion of 5%, 8% and 10%. The supplemented pasta products had shorter cooking time and higher water absorption, cooking and protein losses in water than had control pasta (100% semolina). From sensory evaluation, fortified pasta generally had acceptability similar to control pasta. Cooked pasta with the highest level of substitution (semolina:germinated pigeon pea flour at 10%) was chemically and biologically evaluated and results showed that protein, fat, dietary fibre and mineral contents were improved. Fortified pasta provided more vitamin B₁, B₂, E and antioxidant capacity than did control pasta. Biological assessment of fortified, cooked pasta indicated that true TD and PER value increased by 12% and 64%, respectively, in comparison with control. The germinated pigeon pea flour can be an excellent ingredient to increase the nutritional value of semolina pasta without affecting the sensory properties.     

CHANGES IN THE ACTIVITY AND SUBCELLULAR DISTRIBUTION OF PPO IN 'DELICIOUS' APPLES DURING CONTROLLED ATMOSPHERE STORAGE

Polyphenol oxidase (PPO) activity in 4, 000 × g, 100, 000 × g, 200 × g and soluble fractions of ‘Delicious’ apples was monitored during 28 weeks of controlled atmosphere storage. PPO activity in 4, 000 × g and 100, 000 × g fractions decreased, while that in soluble and 200 × g fractions increased. These shifts in subcellular location occurred sooner in apples which were stored under high CO₂ conditions (2.5–6% O₂, 8–12% CO₂) than those under normal CA conditions (2% O₂, 3% CO₂). Polyacrylamide gel electrophoresis of 4, 000 × g fractions isolated from ‘Delicious’ apples at harvest showed 2 bands with PPO activity, while stored samples all had 3 bands. Isoenzyme patterns were found to vary in different subcellular fractions.     

Use of durum residue flour,a lower value product of durum milling,by incorporation into wheat flour dough without deterioration in baking quality

BACKGROUND: During the milling of durum wheat to semolina, about 10–15% of total products produced is residue flour, a lower value product than the semolina. This study investigated the potential for using the durum residue flour as an additive in bread‐making to improve its potential commercial value. RESULTS: Incorporation of residue durum flour from 102 breeding lines into a low protein flour and standard bakers' flour at 20% incorporation improved the bake loaf volume with minimal change in Mixograph dough mixing time and peak resistance in many of the lines tested. Loaf yellow b was always increased even with only a 10% incorporation. Baking flours can tolerate 20% incorporation with no deleterious affects on loaf volume and bake score. CONCLUSION: The results show a potential for using the lower value durum residue flour for baking bread of acceptable quality with a slightly higher yellow colour. This would improve the profitability for the miller and provide alternative ingredients to the baker for preparing specialty breads. Copyright © 2008 Crown in the Right of the State of New South Wales and Society of Chemical Industry     

Steam blanching effect on polyphenoloxidase,peroxidase and colour of mango (Mangifera indica L.) slices

The heat stability of peroxidase (POD) and polyphenoloxidase (PPO) was investigated in mango (Mangifera indica L.) slices, and the relative colour was studied after different steam blanching times. There was complete inactivation after 5 min for POD and 7 min for PPO. Steam blanching of 3 min gave residual activity of 2.85% and 8.33% for PPO and POD, respectively, and when compared with samples blanched for 5 min had no effect on colour over 20 days of storage. Correlation was found between activities of PPO, POD and colour change over 20 days. After 7 min steam blanching the browning index was stable but less than at 3 and 5 min because non-enzymic browning had occurred. This research suggests that yellowness (b) and lightness (L) values contribute positively to the browning index (BI), compared to redness (a).     

Chemical,biological and sensory evaluation of pasta products supplemented with α‐galactoside‐free lupin flours

α‐Galactoside‐free lupin flour has been used to supplement durum wheat semolina flour in order to increase the nutritive value of pasta products. Supplemented pasta products had a shorter cooking time, higher cooking water absorption, cooking loss and protein loss in water than control pasta prepared with only semolina. Sensory evaluation of cooked pastas showed that products supplemented with 80 g kg^?1 of α‐galactoside‐free Lupinus angustifolius var. Emir flour or with 100 g kg^?1 of α‐galactoside‐free Lupinus angustifolius var. Troll flour showed the same acceptability by panellists as the semolina pasta. These levels of supplementation were selected for further studies. The cooked α‐galactoside‐free lupin/semolina pastas showed higher amounts of protein, dietary fibre, calcium, phosphorus, magnesium, zinc and antioxidant capacity than control pasta and a reasonable level of vitamin B₁, vitamin B₂ and vitamin E. Biological assessment of cooked pastas indicated that the true protein digestibility did not change after the fortification of semolina but protein efficiency ratio increased sharply in the pasta supplemented with α‐galactoside‐free lupin flours (2.07 and 1.92 for Emir and Troll lupin varieties, respectively) in comparison with the control pasta (1.11). It is concluded that the α‐galactoside‐free lupin flours are an adequate ingredient to improve the nutritional quality of pasta products without adding flatulent oligosaccharides. Copyright © 2006 Society of Chemical Industry     

Effect of insoluble dietary fibre addition on technological,sensory, and structural properties of durum wheat spaghetti

Insoluble fibres are important in human health and disease prevention and can be incorporated into food. High fibre pasta prepared with bran is typically inferior quality compared to durum pasta. This study compared spaghetti prepared from durum semolina substituted with various amounts of either durum bran or germ (pollard) dried at high temperature. Pasta was evaluated for cooking properties, texture, sensory, fibre content, antioxidant status (AO) and in vitro starch digestibility to determine the dose producing acceptable quality. Pollard at 10% substitution had minimal impact on quality with higher AO and fibre. Above 30%, pasta had undesirable colour, sensory properties and higher starch digestion. Although bran substituted pasta had undesirable sensory and technological properties, especially at 30% incorporation, it does provide more dietary fibre and antioxidants than regular pasta and does not affect starch digestibility. Interestingly, a significant amount of AO was retained in the cooked pasta. The study illustrates the value of structural analysis to explain observed technological properties of the product with fibre inclusion.     

Gluten-free pasta production from banana and cassava flours with egg white protein and soy protein addition

Egg white protein and soy protein were incorporated into a banana and cassava flour blend (75:25) to produce gluten-free pasta. The objectives of study were to investigate the effects of the different protein sources on the physico-chemical properties of gluten-free pasta. The levels of protein inclusion were 0%, 5%, 10% and 15% of composite flour (w/w) for each type of protein. Pasta made from 100% durum wheat semolina was used as controls. The protein fortification affected the total starch, resistant starch and protein content of gluten-free pasta compared to semolina pasta. No significant effects of soy/egg white protein addition were found in either insoluble or soluble dietary fibre content. Cooking properties of pasta (optimum cooking time, swelling index, water adsorption index and cooking loss) and texture properties (firmness and extensibility) were affected by the level of protein addition and the type of protein. Results showed the utilisation of 25% cassava flour and protein inclusion have a promising application in gluten-free pasta production.     

The effect of pretreatment on the fermentation of honeybush tea (Cyclopia maculata)

Different pretreatments (bruising, hot and cold water) were used to study their effect on fermentation as measured by the quality parameters of honeybush tea (Cyclopia maculata). Bruising and pretreatment with water (hot and cold) were investigated as means to increase the fermentation rate and to improve product quality. The development of the desired dark-brown colour and honey-like flavour during fermentation was faster in hot and cold water treated material and gave a more uniform coloured product than with the bruising pretreatment. Liquor characteristics also improved with water pretreatment. A red–brown extract, compared with the light yellow–brown of untreated samples, was obtained with the water pretreatment. Hot water pretreatment inactivated the enzymes polyphenol oxidase (PPO) and peroxidase (POD), but did not terminate or impair fermentation. The inactivation of the enzymes, together with high temperature (>60°C) fermentation, indicated a chemical oxidation process rather than an enzymatic reaction in honeybush tea fermentation. © 1998 SCI.     

Incorporation of Chlorella vulgaris and Spirulina maxima biomass in pasta products. Part 1: Preparation and evaluation

BACKGROUND: Microalgae are able to enhance the nutritional content of conventional foods and hence to positively affect human health, due to their original chemical composition. The aim of the present study was to prepare fresh spaghetti enriched with different amounts of microalgae biomass (Chlorella vulgaris and Spirulina maxima) and to compare the quality parameters (optimal cooking time, cooking losses, swelling index and water absorption), chemical composition, instrumental texture and colour of the raw and cooked pasta enriched with microalgae biomass with standard semolina spaghetti. RESULTS: The incorporation of microalgae results in an increase of quality parameters when compared to the control sample. The colour of microalgae pastas remained relatively stable after cooking. The addition of microalgae resulted in an increase in the raw pasta firmness when compared to the control sample. Of all the microalgae studied, an increase in the biomass concentration (0.5–2.0%) resulted in a general tendency of an increase in the pasta firmness. Sensory analysis revealed that microalgae pastas had higher acceptance scores by the panellists than the control pasta. CONCLUSION: Microalgae pastas presented very appellative colours, such as orange and green, similar to pastas produced with vegetables, with nutritional advantages, showing energetic values similar to commercial pastas. The use of microalgae biomass can enhance the nutritional and sensorial quality of pasta, without affecting its cooking and textural properties. Copyright © 2010 Society of Chemical Industry     

Evaluation of isoflavone content and antioxidant activity of soy-wheat pasta

The purposes of this work were to determine isoflavones profile and antioxidant activity of two soy flours and spaghetti produced from semolina blended with increasing amount of these flours. Defatted and toasted soy flour (DSF and TSF, respectively) showed different isoflavone profiles though glucosides were the most abundant isoflavone forms in both the meals. The pasta-making procedure determined an increase of the aglycone forms that was at least 37 and 21% in TSF and DSF pasta, respectively. Cooking operations induced severe decreases of the isoflavone content (the losses ranged from 60.44 to104.91 mg kg⁻¹ for TSF pasta and from 85.41 to 469.33 mg kg⁻¹ for DSF pasta). The results of the antioxidant activity were quite different as a function of the methods applied but they resulted generally well correlated with the isoflavone contents of the samples. Cooking induced significant decreases of the antioxidant activity in almost all samples. This result appears well correlated with the decrease of the total isoflavone content and the presence of antioxidant activity in the cooking water.