Xylitol bioproduction from wheat straw: hemicellulose hydrolysis and hydrolyzate fermentation

A 2² central composite design with five center points was performed to estimate the effects of temperature (120, 130 and 140 °C) and acid loading (100, 150 and 200 mg g^?1) on the yield of monomeric xylose recovery from wheat straw hemicellulose (Y_S/RM). Under the best hydrolysis condition (140 °C and 200 mg g^?1), a Y_S/RM of 0.26 g g^?1 was achieved. After vacuum concentration and detoxification by pH alteration and active charcoal adsorption, the hydrolyzate was used as source of xylose for xylitol bioproduction in a stirred tank reactor. A xylitol production of 30.8 g L^?1 was achieved after 54 h^?1 of fermentation, resulting in a productivity (Q_P) of 0.57 g L^?1 h^?1 and bioconversion yield (Y_P/S) of 0.88 g g^?1. The maximum specific rates of xylose consumption and xylitol production were 0.19 and 0.15 g g^?1 h^?1, respectively. Copyright © 2006 Society of Chemical Industry     

Modelling of the hydrolysis of sorghum straw at atmospheric pressure

Sorghum straw is a renewable, cheap and widespread resource. The acid hydrolysis of sorghum straw to obtain xylose solutions could be a good alternative for this abundant resource. The H₂SO₄ hydrolysis of sorghum straw at two different temperatures (80 and 100 °C) and three H₂SO₄ concentrations (2, 4 and 6%) using a solid/liquid ratio of 1:10 (w/w) was studied. Kinetic parameters of mathematical models for predicting the concentrations of xylose, glucose, acetic acid and furfural were determined. The activation energy of the release reaction was 183.3 kJ mol^?1 for xylose and 185.8 kJ mol^?1 for glucose. The optimal conditions found were 6% H₂SO₄ at 100 °C for 60 min, which allow one to obtain a solution with 18.27 g xylose l^?1, 6.78 g glucose l^?1, 0.7 g furfural l^?1 and 1.35 g acetic acid l^?1. It is concluded that this process has potential for utilisation of this renewable lignocellulosic resource. © 2002 Society of Chemical Industry     

Prehydrolysis of xylan in culm of Sasa kurilensis with dilute sulphuric acid

To prepare a substrate for microbial conversion of xylose into xylitol, the culm of Sasa kurilensis was hydrolysed with dilute sulphuric acid. A fermentable substrate with a relatively high xylose concentration (21.9?g?L^?1) was obtained by hydrolysis with 2% sulphuric acid with a liquid to solid ratio of 10?:?1 at 121°C for 1?h. During hydrolysis at elevated temperatures, some undesirable byproducts were also generated, such as degradation products of solubilized sugars and lignin, which are potential inhibitors of microbial metabolism. These compounds were successfully removed from the hydrolysate by treatment with a commercially available activated charcoal (30?g?L^?1 dose).     

Simultaneous lactic acid and xylitol production from vine trimming wastes

Hemicellulosic hydrolyzates from vineshoot trimmings obtained by dilute sulfuric acid hydrolysis were evaluated for xylitol production by Debaryomyces hansenii NRRL Y‐7426. Bioconversion was not efficient, however, since a mixture of products (mainly ethanol) was achieved. Taking into account that hexoses (such as glucose or mannose) can inhibit xylose metabolism by repression and inactivation of the xylose transport system or catabolic enzymes and that these hemicellulosic hydrolyzates are characterized by a high glucose concentration, a novel technology was developed, sequentially transforming glucose into lactic acid by Lactobacillus rhamnosus followed by fermentation of xylose into xylitol by Debaryomyces hansenii after L. rhamnosus removal by microfiltration. Optimal conditions were achieved using detoxified concentrated hemicellulosic hydrolyzates, after CaCO₃ addition in both stages of fermentation and using nitrogen purges after sampling in order to reduce the oxygen dissolved. Under these conditions 31.5 g lactic acid L^?1 (Q_LA = 1.312 g L^?1 h^?1 and Y_LA/S = 0.93 g g^?1) and 27.5 g xylitol L^?1 (Q_Xylitol = 0.458 g L^?1 h^?1 and Y_Xylitol/S = 0.53 g g^?1) were produced. Finally, lactic acid was selectively recovered using the resin Amberlite IRA 400 (0.0374 g of lactic acid g^?1 of dry resin), allowing a further recovery of xylitol by sequential stages of adsorption, concentration, ethanol precipitation, concentration and crystallization to obtain food‐grade xylitol according to a developed process. Copyright © 2007 Society of Chemical Industry     

Revalorisation of vine trimming wastes using Lactobacillus acidophilus and Debaryomyces hansenii

BACKGROUND: Mild acid treatments of vine‐shoot trimmings result in the hydrolysis of hemicellulosic sugars that can be utilised by Lactobacillus acidophilus CECT‐4179 (ATCC 832) and Debaryomyces hansenii NRRL Y‐7426 as carbon sources to obtain food additives. Since the high content of glucose in these hydrolysates reduces the effective bioconversion of xylose into xylitol by D. hansenii, the use of Lactobacillus acidophilus, one of the main probiotic species, allows this problem to be solved by the selective consumption of glucose. In order to use both sugars (glucose and xylose), hemicellulosic vine‐shoot trimming hydrolysates can be sequentially fermented by both micro‐organisms. RESULTS: It was found that, in the first step, L. acidophilus generated almost exclusively lactic acid (32.7 g of lactic acid L^?1, Q_LA = 1.363 g L^?1 h^?1, Y_LA/S = 0.72 g g^?1) by homofermentative degradation of sugars (mainly glucose), and in the second step, the remaining hemicellulosic sugars were transformed primarily into xylitol by Debaryomyces hansenii (31.3 g of xylitol L^?1, Q_Xylitol = 0.708 g L^?1 h^?1, Y_Xylitol/S = 0.66 g g^?1). Furthermore, L. acidophilus proved to be a strong cell‐bounded biosurfactant producer. Cell extracts were able to reduce the surface tension (ST) of PBS in 18 mN m^?1 units. Lactobacillus acidophilus cells showed no difference in viability before or after PBS extraction of biosurfactants, achieving values of 0.9 × 10⁹ colony‐forming units (CFU) mL^?1 in both cases. CONCLUSIONS: These results have made a serious contribution to the re‐evaluation of a useless and pollutant residue, producing a wide range of natural food additives. Copyright © 2008 Society of Chemical Industry     

Improving downstream processes to recover tartaric acid,tartrate and nutrients from vinasses and formulation of inexpensive fermentative broths for xylitol production

BACKGROUND: Vinasses, the main liquid wastes from the distillation process of grape marc and wine lees, are acidic effluents with high organic content, including acids, carbohydrates, phenols, and unsaturated compounds with high chemical oxygen demand, biological oxygen demand and solid concentrations. These wastes can be revalued to provide additional benefits when they are employed as feedstock of some compounds including tartaric acid, calcium tartrate and economic nutrients for the elaboration of fermentable broths. RESULT: This study attempts to recover tartaric acid and calcium tartrate from vinasses. All the tartaric acid initially solubilised was recovered in both processes. The residual streams can be successfully employed as economic nutrients for the xylose to xylitol bioconversion, achieving higher global volumetric productivities (Q_{P, xylitol} = 0.232 g L^?1 h^?1) and products yields (Y_xylitol/S = 0.57 g g^?1) than fermentations carried out using commercial nutrients (Q_{P, xylitol} = 0.193 g L^?1 h^?1 and Y_xylitol/S = 0.55 g g^?1 respectively). CONCLUSION: Tartaric acid can be recovered from vinasses in the form of tartaric acid crystals and calcium tartrate. The residual streams generated in the process can be used as economic nutrients for the production of xylitol by D. hansenii. Copyright © 2010 Society of Chemical Industry     

Effect of added glucose and xylose on the fermentation of perennial ryegrass silage inoculated with Lactobacillus plantarum

Perennial ryegrass (Lolium perenne L) was ensiled in laboratory silos after addition of glucose or xylose at rates of 0, 25, 35 and 45 g kg^?1 fresh grass. In addition, an inoculum of Lactobacillus plantarum, supplying 10⁶ organisms g^?1 fresh grass, was applied to all treatments. Silos were opened after 7, 21 and 100 days and the silage was subjected to chemical and microbiological analysis. AH silages were well fermented with pHs between 3·60 and 3·70 and low NH₃-N concentrations (<95 g kg^?1 total nitrogen) and an absence of butyric acid. Glucose was virtually completely consumed within 21 days but 0·30–0·50 of the xylose doses remained after 100 days. Lactic acid concentrations were not increased by the addition of sugars, but the glucose treatments were associated with very high concentrations of ethanol, 60–100 g kg^?1 DM, and the xylose additions produced very high concentrations of acetic acid, 60–135 g kg^?1 DM. Most(>0·80) of the glucose that disappeared could be accounted for in ethanol formation but the xylose consumed could be accounted for only if the lactic acid produced in its fermentation was metabolised further to acetic acid; indeed, for the two higher doses of xylose, the concentrations of lactic acid were reduced from the control value of 177 g kg^?1 DM to 140 and 120 g kg^?1 DM, respectively. The results indicate that the provision of extra sugar, as hexose or pentose, allows yeasts to assume a more prominent role in the fermentation with consequent wasteful fermentation of sugars. Furthermore, the suggestion is that xylose may indirectly, via a stimulation of lactate-assimilating yeasts, encourage further metabolism of lactic acid to acetic acid.     

Aflatoxin B1, ochratoxin A and zearalenone in sorghum grains marketed in Tunisia

A total of 64 samples of sorghum (37 Tunisian sorghum samples and 27 Egyptian sorghum samples) were collected during 2011–2012 from markets in Tunisia. Samples were analysed for contamination with aflatoxin B1, ochratoxin A and zearalenone by High-Performance Liquid Chromatography Coupled with Fluorescence Detection (HPLC-FLD). Aflatoxin B1 was found in 38 samples in the range 0.03–31.7 µg kg^?1. Ochratoxin A was detected in 24 samples with concentrations ranging from 1.04 to 27.8 µg kg^?1. Zearalenone was detected in 21 samples and the concentration varied between 3.7 and 64.5 µg kg^?1. ANOVA analysis of the influence of the country of origin on the incidence and concentration of mycotoxins in the samples studied showed no significant difference (P > 0.05) between the two batches of samples for each of the three mycotoxins studied. The studied mycotoxins contaminate sorghum and may also co-exist because of the diversity of the mycobiota in this cereal.     

Risk assessment of patulin intake through apple-based food by infants and preschool children in Serbia

ABSTRACT

This study reports for the first time in Serbia the occurrence of patulin in apple-based food and the risk assessment associated with patulin intake by infants and preschool children. In total, 214 samples of infant fruit juices (48), infant purée (66), and juices for children (small package with straw, 100) were collected over 3 years (2013–15) and analysed using HPLC with ultraviolet detection. Patulin was found in 43.8% of infant juices and 16.7% of infant purée, with all values below the legal limit of 10 μg kg^?1 (maximum 8.3 and 7.7 μg kg^?1, respectively). The proportion of contaminated samples among fruit juices for children was 43.0%, with the highest patulin concentration at 30.2 μg kg^?1, not exceeding the maximum allowed level of 50 μg kg^?1. Risk assessment of patulin intake by Serbian infants and preschool children, conducted by deterministic and probabilistic approaches, revealed a hazard quotient well below 1, indicating a tolerable exposure level and no health concern.     

Nutritional quality of uncultivated cereal grains utilised as famine foods in western sudan as measured by chemical analysis

The chemical composition of the grain of a number of wild grasses used as food in times of famine in western Sudan are reported and compared with those of the local staple cereals. Species investigated were Cenchrus hiflorus (haskaneet). Dactyloctenium aegyptium (korecb). Echinochloa colona (difra) and Oryza punctata (ruz el wadi). The grain of all species except C biflorus had protein contents in the range 110-140 g kg^?1, broadly similar to those of the local staple cereals. The grain of C biflours possessed a particularly high protein content of 210 g kg^?1. The nutritional quality of the proteins as measured by their chemical scores ranged from 20 for C biflorus to 65 for O punctata compared with scores of 36 and 58 for the local sorghum var Kurgi and millet respectively. Lysine was the limiting amino acid in all cases. Whilst the composition of the protein of sorghum var Kurgi was typical of sorghum generally, that of var Karamaka was unusual in possessing lysine levels of 3.4 g (16 g N)¹, double that normally present in sorghum and raising the chemical score of the protein to 62. The ash content of the famine food cereals was high, attaining 113 g kg¹ in C biflorus. All grains were good sources of zinc and D aegyptium. O punctata and E colonum additionally contained comparatively high levels of iron. Remarkably for a cereal D aegyptium was also very rich in calcium, containing over 10 g kg¹, and possessed high concentrations of manganese. Carbohydrate content of the famine food grains varied from 617 g kg¹ for C biflorus to 748 g kg¹ for O punctata, values comparable to the local staple cereals. The proportion of starch in this fraction ranged from 650 g kg¹ in D aegyptium to 940 g kg¹ in O punctata. Seed oils of all species were predominantly unsaturated containing mainly oleic and linoleic acids.     

Potential of aflatoxin B1 production by Aspergillus flavus strains on commercially important food grains

In this study, we investigated the potential of aflatoxin B₁ (AFB1) production by five Aspergillus flavus strains previously isolated from sorghum grains on cereals (barley, maize, rice, wheat and sorghum), oilseeds (peanuts and sesame) and pulses (greengram and horsegram). Five strains of A. flavus were inoculated on all food grains and incubated at 25 °C for 7 days; AFB1 was extracted and estimated by enzyme‐linked immunosorbent assay. All A. flavus strains produced AFB1 on all food grains ranging from 245.4 to 15 645.2 μg kg^?1. Of the five strains tested, strain Af 003 produced the highest amount of AFB1 on all commodities ranging from 2245.2 to 15 645.2 μg kg^?1. Comparatively, the AFB1 accumulation was high on rice grains ranging from 3125.2 to 15 645.2 μg kg^?1, followed by peanuts ranging from 2206.2 to 12 466.5 μg kg^?1. Less AFB1 accumulation was observed in greengram and sesame seeds ranging from 645.8 to 2245.2 and 245.4 to 2890.6 μg kg^?1, respectively. Our results showed that all food grains tested are susceptible to A. flavus growth and subsequent AFB1 production.     

Production of fermentable media from vine‐trimming wastes and bioconversion into lactic acid by Lactobacillus pentosus

Trimmings of vineshoots, an agricultural waste with little use, were hydrolysed with dilute sulphuric acid (1–5%) in order to obtain sugar solutions suitable as fermentation media. The operational conditions for hydrolysis were selected on the basis of both the generation of hemicellulosic sugars (mainly xylose) and glucose and the concentrations of reaction byproducts affecting fermentation (furfural, hydroxymethylfurfural and acetic acid). Hemicellulosic hydrolysates were supplemented with nutrients and fermented with Lactobacillus pentosus, without any previous detoxification stage, to produce lactic acid. Under the best operational conditions assayed (3% H₂SO₄ and 15 min), 21.8 g lactic acid l^?1 was produced (Q_P = 0.844 g l^?1 h^?1, Y_P/S = 0.77 g g^?1), which represents a theoretical yield of 99.6%. Acetic acid was the primary byproduct formed from xylose, at about 25% of the lactic acid level. Copyright © 2004 Society of Chemical Industry     

Micronutrients (B,Co, Cu,Fe, Mn,Mo, and Zn) content in made tea (Camellia sinensis L.) and tea infusion with health prospect: A critical review

Tea (Camellia sinensis L.) is a perennial acidophilic crop, and known to be a nonalcoholic stimulating beverage that is most widely consumed after water. The aim of this review paper is to provide a detailed documentation of selected micronutrient contents, viz. boron (B), cobalt (Co), copper (Cu), iron (Fe), manganese (Mn), molybdenum (Mo), and zinc (Zn) in made tea and tea infusion. Available data from the literature were used to calculate human health aspect associated with the consumption of tea infusion. A wide range of micronutrients reported in both made tea and tea infusion could be the major sources of micronutrients for human. The content of B, Co, Cu, Fe, Mn, Mo, and Zn in made tea are ranged from 3.04 to 58.44 μg g^?1, below detectable limit (BDL) to 122.4 μg g^?1, BDL to 602 μg g^?1, 0.275 to 13,040 μg g^?1, 0.004 to 15,866 μg g^?1, 0.04 to 570.80 μg g^?1 and 0.01 to 1120 μg g^?1, respectively. Only 3.2 μg L^?1 to 7.25 mg L^?1, 0.01 μg L^?1 to 7 mg L^?1, 3.80 μg L^?1 to 6.13 mg L^?1, 135.59 μg L^?1 ?11.05 mg L^?1, 0.05 μg L^?1 to 1980.34 mg L^?1, 0.012 to 3.78 μg L^?1, and 1.12 μg L^?1 to 2.32 μg L^?1 of B, Co, Cu, Fe, Mn, Mo, and Zn, respectively, are found in tea infusion which are lower than the prescribed limit of micronutrients in drinking water by World Health Organization. Furthermore, micronutrient contents in tea infusion depend on infusion procedure as well as on the instrument used for analysis. The proportion of micronutrients found in different tea types are 1.0–88.9% for B, 10–60% for Co, 2.0–97.8% for Cu, 67.8–89.9% for Fe, 71.0–87.4% for Mn, 13.3–34% for Mo, and 34.9–83% for Zn. From the results, it can also be concluded that consumption of three cups of tea infusion per day does not have any adverse effect on human health with respect to the referred micronutrients rather got beneficial effects to human.     

Assessment of nutritional compounds and antinutritional factors in pea (Pisum sativum) seeds

The nutrient and antinutritional factor content of 18 pea lines was studied. The following levels were found: non‐protein nitrogen 5.2–10.2 g kg^?1 DM, protein nitrogen 35.3–42.4 g kg^?1 DM, lysine 50.7–76.3 g kg^?1 protein DM, histidine 17.8–24.8 g kg^?1 protein DM, tyrosine 22.6–30.0 g kg^?1 protein DM, protein 25.9–31.9% DM, in vitro protein digestibility 89.3–95.6%, vitamin B₁ 5.9–10.3 mg kg^?1 DM, vitamin B₂ 1.1–3.7 mg kg^?1 DM, sucrose 11.6–25.4 g kg^?1 DM, raffinose 4.1–10.3 g kg^?1 DM, stachyose 10.7–26.7 g kg^?1 DM, verbascose 0.0–26.7 g kg^?1 DM, total α‐galactosides 22.6–63.4 g kg^?1 DM, trypsin inhibitor activity 0.8–8.4 TIU mg^?1 DM, inositol hexaphosphate 2.3–6.5 g kg^?1 DM, inositol pentaphosphate 0.1–1.8 g kg^?1 DM and total inositol phosphates 2.8–7.1 g kg^?1 DM. Peas with yellow cotyledons had the highest trypsin inhibitor activities, those with light green cotyledons had the highest lysine contents, and those with dark green cotyledons were the richest in vitamins B₁ and B₂. Peas with brown testae had the lowest verbascose and sucrose contents, while they were the richest in inositol hexaphosphate. Smaller peas were characterised by the highest protein nitrogen contents as well as the highest contents of vitamins B₁ and B₂, verbascose and inositol pentaphosphate. Peas of medium size showed the lowest verbascose, α‐galactoside and vitamin B₂ contents. Bigger peas showed the lowest inositol pentaphosphate contents. © 2003 Society of Chemical Industry     

Integral utilisation of barley husk for the production of food additives

A new and effective chemical–biotechnological process for the global utilisation of barley husk (obtained from the spent grains in the brewing process) is reported. With the proposed process the three main components of the lignocellulosic residue (cellulose, hemicellulose and lignin) are utilised. A first treatment with sulfuric acid (pre‐hydrolysis) allowed the solubilisation of hemicelluloses to give xylose and glucose‐containing liquors (suitable to make fermentation media for the continuous lactic acid (LA) production with L. pentosus) and a solid phase containing cellulose and lignin. In this set of experiments, a maximum volumetric productivity (Q_P) = 2.077 g L^?1 h^?1 and product yield (Y_P/S) = 0.62 g g^?1 were obtained for a dilution rate of 0.01 h^?1. The solid residues from pre‐hydrolysis were treated with NaOH in order to increase their cellulase digestibility, and dissolve the lignin content. The cellulose residue was used as substrates for lactic acid production by simultaneous saccharification and fermentation (SSF) in media containing Trichoderma reesei cellulases and Lactobacillus rhamnosus cells using the complete MRS broth or a cheaper medium. In both cases similar LA concentrations and volumetric productivities were achieved (P = 73.4–71.0 g L^?1 and Q_P = 1.28–1.25 g L^?1 h^?1, respectively), where P is LA concentration. The lignin solution obtained after the alkaline treatment was extracted with ethyl acetate in order to obtain the phenolic components. The extract obtained at pH 3 showed three times more antioxidant activity than the one extracted at pH 12.8, with an EC₅₀ of 1.396 g L^?1 for pH 3 and 4.604 g L^?1 for pH 12.8. The best extracts showed twice antioxidant activity than BHT. Copyright © 2007 Society of Chemical Industry     

Validation and quantification of neonicotinoid insecticide residues in rice whole grain and rice straw using LC-MS/MS

An efficient analytical method was developed and validated using a modified QuEChERS method and LC-MS/MS for the detection and quantification of neonicotinoid insecticide residues in rice whole grain and rice straw. The samples were extracted using acetonitrile and cleaned up by dispersive solid-phase extraction. Validation based on five fortification levels showed good recoveries of neonicotinoids ranging from 75% to 116 % and 60% to 105 % for rice whole grain and straw, respectively. The precision ranged between 3% and 17 %, and 2% and 10 % for grain and straw, respectively. The limit of detection was from 0.007 to 0.0084 mg kg^?1 and 0.005 to 0.15 mg kg^?1 and the limit of quantification was in the range of 0.024–0.028 mg kg^?1 and 0.016–0.051 mg kg^?1 for rice whole grain and rice straw, respectively. Monitoring of farm gate samples indicated that, out of 24 samples, 1 rice whole grain sample was contaminated with thiamethoxam residues (0.07 mg kg^?1).     

Survey of fumonisins B1, B2 and B3 in conventional and organic retail corn products in Spain and Italy and estimated dietary exposure

A survey was conducted to determine the occurrence of fumonisin B₁, B₂ and B₃ during 2007 in 186 samples of organic and conventional locally available corn products. Samples included baby food (n = 62), corn flour (11), cornflakes (23), pasta (14), cookies (17) and other corn products (59) were obtained from popular markets of Valencia (Spain) and Perugia (Italy). The analytical method used pressurized liquid extraction and liquid chromatography/electrospray ionization tandem mass spectrometry with a triple quadrupole (QqQ) analyser. Of the 104 Spanish samples, 22% contained levels in the range of 2–449 µg kg^?1, 2–229 µg kg^?1 and 6–105 µg kg^?1 for FB₁, FB₂ and FB₃, respectively, while 19 (23%) of the 82 Italian samples were positive with quantifiable levels between 2–235 µg kg^?1, 3–187 µg kg^?1, and 4–40 µg kg^?1 for fumonisins B₁, B₂ and B₃, respectively. Overall, none of the Italian samples and only one organic baby food sample from a Spanish market was above the maximum permitted levels established by European legislation. Fumonisins were found mostly in corn flour followed by cookies and cornflakes. Eleven samples from Spain and nine samples from Italy were organic products, being contaminated the 72% and 77% of the samples, respectively. Analysis of the results showed that levels of fumonisins in corn products were similar in Italy and Spain. The safety of fumonisin intake through corn products was demonstrated by the calculation of the estimated daily intake of both populations considering organic and conventional products separately, which ranged from 1.7 × 10^?3 to 0.72 µg kg^?1 bw day^?1 and comparing them with the provisional maximum total daily intake (PMTDI) of 2 µg kg^?1 bw day^?1 established by the European Union.     

A Cassava Starch–Chitosan Edible Coating Enriched with <Emphasis Type="Italic">Lippia sidoides</Emphasis> Cham. Essential Oil and Pomegranate Peel Extract for Preservation of Italian Tomatoes (<Emphasis Type="Italic">Lycopersicon esculentum</Emphasis> Mill.) Stored at Room Temperature

The effect of edible cassava starch–chitosan coatings incorporated with rosemary pepper (Lippia sidoides Cham.) essential oil and pomegranate peel extract on the shelf-life of tomatoes during storage at 25 °C for 12 days was investigated. Sixteen formulations, containing 10 g L^?1 cassava starch and various concentrations of chitosan (5, 10, 20, 30 g L^?1), essential oil (0, 2.5, 5, 10 mL L^?1) and pomegranate peel extract (0, 5, 10, 20 mL L^?1) were prepared and applied to tomatoes. Physical–chemical and microbiological analyses were performed on days 1, 4, 8 and 12. Most of the coatings delayed the ripening of tomatoes, lowering the total soluble solids (38?44 g sucrose kg^?1) and weight loss (93?128 g kg^?1) and maintaining constant firmness compared to the uncoated tomatoes (45 g sucrose kg^?1, 175 g kg^?1) at 12 days of storage. Conversely, except red intensity (a*), which was higher for the uncoated samples, the colour parameters (L*, b*) of the coated and control tomatoes were similar at the end of storage. Uncoated and coated tomatoes showed no contamination during storage. The coatings showed potential to maintain the quality of tomatoes during storage at 25 °C for 12 days. In this context, tomatoes coated with the formulation comprising 10 g L^?1 cassava starch, 10 g L^?1 chitosan, 10 mL L^?1 essential oil and 20 mL L^?1 pomegranate peel extract showed the lowest weight loss and reduced total soluble solids content compared with uncoated ones.     

Effect of flaxseed and wheat flour blends on dough rheology and bread quality

The rheological and baking properties of flaxseed/wheat composite flours were studied. Flaxseed flour was used to replace 50, 100, 150 and 200 g kg^?1 of wheat flour in bread. Farinographic studies showed that water absorption, dough development time and mixing tolerance index increased as the amount of flaxseed flour increased, while dough stability decreased at 100, 150 and 200 g kg^?1 of flaxseed flour substitution. The extensographic energy of dough also decreased at 150 and 200 g kg^?1 flaxseed levels. The addition of increasing amounts of flaxseed flour caused a decrease in extensibility. Doughs containing 100, 150 and 200 g kg^?1 flaxseed flour showed resistance to extension comparable to that of control dough. The specific volume of flaxseed flour breads was similar to that of control bread. Crust L, a, b values of breads with flaxseed flour were lower than those of control bread. Breads with flaxseed flour gave lower crumb L and b values and higher a values than control bread. The sensory properties showed that an acceptable bread could be produced using flaxseed flour up to a level of 200 g kg^?1. Copyright © 2007 Society of Chemical Industry     

Characterisation and functional properties of proteins of some Indian chickpea (Cicer arietinum) cultivars

BACKGROUND: Chickpea (Cicer arietinum L.) proteins have received attention during recent years owing to their higher biological values and better functional ingredients than oilseed proteins. In this study the composition, fractionation, electrophoretic behaviour and functional properties of five chickpea protein concentrates were determined. RESULTS: The chickpea proteins contained 15.9–54.8 g kg^?1 albumin, 48.9–154.1 g kg^?1 globulin, 39.2–76.5 g kg^?1 glutelin and traces of prolamin. Electrophoresis of the various fractions revealed that albumin and globulin were made up of sub‐units of different molecular weights ranging from 7 to 96 kDa. Water and oil absorption of the protein concentrates varied from 1.15 to 2.75 g g^?1 and from 2.60 to 5.65 g g^?1 respectively. Foaming capacity and foam stability of the protein concentrates were good and improved with the addition of salt (10 g L^?1 NaCl) or sugar (100 g L^?1 sucrose) at both isoelectric and neutral pH. Emulsifying capacity and emulsion stability of the protein concentrates were good and excellent respectively. CONCLUSION: Protein concentrates prepared from chickpeas have potential use in food formulations owing to their good emulsifying/foaming and water/oil‐binding capacities. Copyright © 2008 Society of Chemical Industry