Optimization of alkylresorcinols extraction from triticale bran using response surface methodology

Optimization conditions for alkylresorcinols (ARs) extraction from triticale bran were determined using response surface methodology. A central composite design was used to determine the effects of extraction temperature (degrees Celsius) and solid-to-solvent ratio (weight per volume) on yield of saturated, unsaturated and total ARs. Extraction of ARs was affected significantly (p value????0.05) by temperature and solid-to-solvent ratio on the yield of saturated, unsaturated and total ARs. The highest quantity of total ARs from triticale bran was extracted at 24?°C between 16 and 24?h at a solid-to-solvent ratio (weight per volume) of 1:40 and ranged from 278 to 308?mg/100?g, while saturated and unsaturated ARs were 163 to 225?mg/100?g and 22 to 29?mg/100?g, respectively. The ARs identified by high-performance liquid chromatography included: C15:0, C17:0, C19:0, C21:0, C23:0 and C25:0. Also some unsaturated analogues (12.4% to 14.0%) were found including C17:1, C19:1, C21:1 and C23:1. Analysis of variance (p value?=?0.05) indicated that the response surface methodology (RSM) developed for saturated, unsaturated and total ARs were adequate and explained most of the variability (85% to 89%) with high coefficient of multiple determination (R ²?=?0.89). The main effect of the response variable was quadratic rather than a linear function. Our results showed that RSM is a tool that is useful to optimise experimental conditions for the extraction of ARs.     

Effects of supercritical fluid extraction parameters on lycopene yield and antioxidant activity

The effects of various parameters of supercritical carbon dioxide (SC-CO₂) fluid extractions of tomato skins on the extraction yields and antioxidant activities of lycopene-rich extracts were investigated. A Box–Behnken design was applied to study the effects of three independent variables (temperature ranging from 40 to 100 °C, pressure ranging from 20 to 40 MPa, and flow rate ranging from 1.0 to 2.0 mL/min) on lycopene yield. The model showed good agreement with the experimental results, by the coefficient of determination (r² = 0.9834). Temperature, pressure, and the quadratic term for the temperature of SC-CO₂ extraction were large significantly positive factors affecting lycopene yield (P < 0.05). The maximum total lycopene content of 31.25 μg/g of raw tomato was extracted at the highest temperature of 100 °C, 40 MPa and 1.5 mL/min. TEAC assay was applied to assess the antioxidant activity of lycopene-rich extracts from SC-CO₂ fluid extraction. The effects of SC-CO₂ fluid extraction parameters on the antioxidant activities of the extracts differed with the yield. For each unit of lycopene extract, the antioxidant activity level was constant below 70 °C, but then gradually decreased above 70 °C due to isomerization occurring as a result of the higher temperature. The ratio of all-trans-lycopene to the cis-isomers changed from 1.70 to 1.32 when the operating temperature was adjusted from 40 to 100 °C, indicating an increased bioavailability due to the generation of the cis-isomers. No significant effects of pressure or flow rate of SC-CO₂ fluid extraction on the antioxidant activity were observed.     

Extraction behaviors of caffeine and chlorophylls in supercritical decaffeination of green tea leaves

The decaffeination of green tea using supercritical carbon dioxide (SC-CO₂) was optimized by response surface methodology (RSM) for the maximal removal of caffeine, and the coextration of chlorophylls was also monitored during decaffeination. The experimental conditions for the SC-CO₂ extraction of caffeine were set up according to the Box-Behnken design of RSM. The relationships between the extraction yield of caffeine and various parameters used for the SC-CO₂ extraction such as pressure, temperature and concentration of ethanol were studied at a fixed CO₂ flow rate. The extraction yields of caffeine and total chlorophyll were significantly influenced by extraction pressure, temperature and concentration of cosolvent, and their extraction yields behaved almost in parallel at different extraction conditions that were obtained by varying pressure, temperature and ethanol cosolvent concentration. At the optimal decaffeination conditions such as 3.0 g of 95% (v/v) ethanol cosolvent per 100 g of CO₂, 23 MPa, 63 °C and an extraction duration of 120 min for 10 g of green tea leaves, the extraction yields for caffeine and catechins were 96.60% (w/w) and 40.61% (w/w), respectively, and the substantial coextraction of total chlorophyll (43.09% of the total amount) was also observed during the decaffeination process.     

Extraction of oil from tiger nut (Cyperus esculentus L.) with supercritical carbon dioxide (SC-CO2)

Supercritical carbon dioxide (SC-CO₂) was used to extract oil from tiger nuts and the physicochemical properties and the impact of extraction conditions [i.e., temperature (40 °C–80 °C), pressure (20–40 MPa) and time (60–360 min)] on the oil yield were studied. The response surface analysis results revealed that the oil yield was significantly (P < 0.05) influenced by the main effect of the extraction pressure, extraction time and their quadratic effects respectively. However, the interaction between the extraction temperature and time had no significant (P > 0.05) effect on the oil yield. The highest oil yield was 26.28 g/100 g sample after 210 min of extraction time at 30.25 MPa and 60 °C respectively. The fatty acid composition of oils obtained by SC-CO₂ and Soxhlet showed marked variation. Also, the fatty acid composition varied depending on the operating conditions. The viscosity of the oil decreased with the increase in temperature.     

Effects of supercritical CO2 fluid parameters on chemical composition and yield of carotenoids extracted from pumpkin

Pumpkin is a traditional food that is grown extensively worldwide and is believed to be beneficial to human health due to its high contents of carotenoids. The carotenoids in pumpkin were extracted by organic solvents and by supercritical carbon dioxide (SC-CO₂), and then they were identified, quantified, and compared. β-carotene (31 to 40 g per 100 g of total carotenoids) was the predominate carotenoid in pumpkin. Lutein and lycopene contents were much higher in SC-CO₂ extracts than those in organic solvent extract. Cis-β-carotene increased by more than two times in the SC-CO₂ extracts, even at a relatively low temperature of 40 °C, over those in the solvent extracts, indicating both enhanced solubility and isomerization from trans- to cis-β-carotene. The influences of modifier (10 mL/100 mL), temperature (40-70 °C), and pressure (25-35 MPa) of SC-CO₂ extraction on the change of carotenoid yields were also investigated. The highest yield (109.6 μg/g) was obtained at 70 °C and 35 MPa, with a 73.7% recovery. Selective extraction could be achieved by adjusting the temperature and pressure. Higher proportions of all-trans-β-carotene extracts were achieved at 40 °C under both 25 MPa and 35 MPa conditions. In order to extract more cis-isomers, a higher temperature of 70 °C was preferred.     

Triticale bran and straw: Potential new sources of phenolic acids,proanthocyanidins, and lignans

The distribution of phenolic acids (free and bound), proanthocyanidins, and lignans in defatted triticale bran and straw was determined. For comparison, wheat, rye and oat brans as well as triticale flakes and leaves were also assayed. Most phenolic acids were present in the bound form (89–98%), and released under alkaline extraction conditions. The content of phenolic acids ranged from 65.2 to 252.5 mg/100 g in samples in which ferulic acid predominanted. Triticale straw was the richest source of proanthocyanidins, containing 862.5 mg/100 g (catechin equivalents) of tissue. Triticale straw contained 0.27 mg/100 g of lignan secoisolariciresinol diglucoside (SDG), whereas the bran had only 0.01 mg/100 g. The oxygen radical absorbance capacity (ORAC, μM Trolox equivalents/g defatted material) showed that antioxidant activity of bound phenolics was higher than those of free phenolics. This is the first report on phenolic acids, proanthocyanidin, and lignans content of Canadian triticale by-products, indicating that they may have the potential for use as nutraceuticals and/or functional food ingredients.     

Development of low-fat gluten and starch fried matrices with high fiber content

Low-fat and high dietary-fiber diets are important elements in the prevention of chronic diseases. The objective of this work was to understand the effect of wheat bran inclusion in large amounts to a gluten–starch matrix, in structure formation and associated quality attributes, during deep-fat frying. Matrices were prepared mixing 12 g of gluten and 88 g of wheat starch per 100 g of dry solids, ensuring a moisture content of 40 g water/100 g dough. Starch was gradually replaced by wheat bran (up to 40 g/100 g dry solids), and lack of structure formation was overcome by partially replacing starch with pregelatinized corn starch. Samples were fried at 170 °C and oil absorption in high fiber products was reduced through post-frying centrifugation. Pregelatinized corn starch addition allowed obtaining an adequate structure in formulations with high wheat bran content, reducing oil absorption by 35% in formulations with up to 20 g wheat bran/100 g dry solids. It was possible to obtain a low-fat product (70% reduction) with high fiber content (40 g/100 g dry solids) after centrifugation, confirming the importance of oil absorption during post-frying cooling.     

Extraction of α-tocopherol and γ-oryzanol from rice bran

The aim of this research was to study the effect of operating mode (continuous versus batch+continuous), temperature, pressure and solvent on α-tocopherol and γ-oryzanol extraction from rice bran (Oryza sativa Linn.) and compare the efficiency of three extraction methods: SC-CO₂ extraction, solvent extraction and soxhlet extraction. Three sets of experiments were performed. First, extraction using SC-CO₂ was performed over a range of temperatures and pressures (45-65 °C and at 38 and 48 MPa), and at a CO₂ flow rate of 0.45 mL/min. The results showed that the best conditions for α-tocopherol extraction were 55 °C, 48 MPa in the batch+continuous mode. For γ-oryzanol, the best conditions were 65 °C, 48 MPa and in the continuous mode. In the second set of experiments, solvent extraction using hexane and ethanol at 32 and 55-60 °C was studied. The results showed that none of the solvents could extract α-tocopherol; however, ethanol at 55-60 °C was suitable for γ-oryzanol extraction. Finally, soxhlet extraction experiments using hexane for α-tocopherol and ethanol for γ-oryzanol were also performed. In summary, SC-CO₂ was found to be the best solvent for extracting both α-tocopherol and γ-oryzanol from rice bran, because of its higher yields and extraction rate.     

Optimization of SC-CO2 extraction of oil from almond pretreated with autoclaving

Supercritical carbon dioxide (SC-CO₂) extraction parameters affecting oil recovery from almond were optimized through response surface methodology (RSM). The optimum extraction conditions were as follows: extraction pressure, 44.1 MPa; extraction temperature, 43.8 °C; dynamic extraction time, 93.6 min; and CO₂ flow rate, 10.1 mL/min. Under these conditions, a mean value of 86.54 ± 0.66 g/100 g (n = 3) was observed, which is well matched with the predicted value of 87.32 g/100 g. Furthermore, the effects of autoclaving pretreatment for the almond particles on the oil recovery, fatty acids' composition, and almond particles' microstructure were also investigated by calculating the percentages of the oil yield, gas chromatograph fitted with a mass spectrometer (GC-MS), and scanning electron microscopy (SEM) analysis, respectively. The results showed that autoclaving pretreatment had minor modifications of the fatty acids' profile of the extracted oil, but greatly promoted the disturbing of almond cell walls, and increased the oil recovery by 6.44%.     

Optimization of Supercritical Carbon Dioxide Extraction of Bioactive Flavonoid Compounds from Spearmint (<Emphasis Type="Italic">Mentha spicata</Emphasis> L.) Leaves by Using Response Surface Methodology

The bioactive flavonoid compounds of spearmint (Mentha spicata L.) leaves were obtained by using supercritical carbon dioxide (SC-CO₂) extraction. Extraction was carried out according to face-centred central composite design, and independent variables were pressure (100, 200 and 300 bar), temperature (40, 50 and 60 °C) and co-solvent amount (3, 6 and 9 g/min). The extraction process was optimized by using response surface methodology for the highest crude extraction yield of bioactive flavonoid compounds. The optimal conditions were identified as 209.39 bar pressure, 50.00 °C temperature and 7.39 g/min co-solvent amount. The obtained extract under optimum SC-CO₂ condition was analysed by high-performance liquid chromatography. Seven bioactive flavonoids including catechin, epicatechin, rutin, luteolin, myricetin, apigenin and naringenin were identified as major compounds. The results of quantification showed that spearmint leaves are potential source of antioxidant compounds.     

Proximate composition and extraction of carotenoids and lipids from Brazilian redspotted shrimp waste (Farfantepenaeus paulensis)

The chemical composition of redspotted shrimp (Penaeus paulensis) waste was investigated. The shrimp waste (freeze-dried heads, shells and tails) was found to have high protein (49% d.w.) and ash (27% d.w.) contents, but a low lipid content (4.9% d.w.) although the latter was higher than those found in other kinds of shrimp captured in Brazil. The fatty acid compositions showed that the lipids had a high content of unsaturated fatty acids, mainly EPA (C20:5; n-3) and DHA (C22:6; n-3). In order to establish an efficient and environmentally friendly recovery process for the astaxanthin (principal carotenoid and antioxidant present in the waste), the following processes were examined: traditional solvent extraction (TSE), super-critical fluid extraction (SC-CO₂) and super-critical fluid extraction with co-solvent (SC-CO₂ + ethanol). The temperature and pressure conditions for all the SC-CO₂ extractions were 50 °C and 30.0 MPa. The results showed that the mixture of 60% (v/v) n-hexane:isopropyl alcohol gave the highest (53 mg/kg waste) carotenoid extraction yield as compared to acetone, SC-CO₂ and SC-CO₂ + ethanol. The SC-CO₂ showed the lowest extraction yield of astaxanthin, but the addition of the entrainer (10% w/w) produced an important effect, increasing the astaxanthin extraction to values of 57.9%, similar to extraction with acetone (63.3%).     

Response surfaces of hazelnut oil yield in supercritical carbon dioxide

Response Surface Methodology was used to determine the effects of solvent flow rate (1, 3 and 5 g/min), pressure (300, 375 and 450 bar) and temperature (40, 50 and 60 °C) on hazelnut oil yield in supercritical carbon dioxide (SC-CO₂). Oil yield was represented by a second order response surface equation (R²=0.997) using Box-Bhenken design of experiments. Oil yield increased with increasing SC-CO₂ flow rate, pressure and temperature. The maximum oil yield was predicted from the response surface equation as 0.19 g oil/g hazelnut (34% of initial oil) when 4 g hazelnut particles (particle diameter<0.85 mm) were extracted with 5 g/min SC-CO₂ flow rate at 450 bar, and 60 °C for 10 min. Total extraction time at these conditions was predicted to be 35 min.     

Physicochemical,rheological and sensory properties of Egyptian Kariesh cheese containing wheat bran

The physicochemical, rheological and sensory properties during the storage of Kariesh cheeses made with 0.1, 0.2, 0.3, 0.4 or 0.5 g wheat bran/100 g milk were evaluated at 0, 7 and 15 days. The cheeses with 0.5 g wheat bran/100 g milk had a significantly (P < 0.01) higher yield and moisture content, and lower pH and protein content than the control. No significant differences (P > 0.01) in salt and ash contents were observed among the cheeses studied. Texture profile analysis showed that the rheological characteristics decreased significantly in cheeses made with wheat bran. These results suggested that wheat bran (up to 0.4%) can be used to produce a fibre fortified Kariesh cheese.     

Effect of addition of protein concentrates from natural and yeast fermented rice bran on the rheological and technological properties of wheat bread

The effect of substituting wheat flour with 0%, 5%, 10% and 15% protein concentrates from natural and yeast fermented rice bran on the rheological properties of their dough and bread properties was studied. Rheological properties of wheat dough were influenced by addition of rice bran protein concentrates. Overall acceptability score and specific loaf volume of 100% wheat bread were not significantly different from composite bread up to 10% rice bran protein substitution, and therefore, the optimised level of substitution was established. The optimised composite bread contained higher total amino acid content, radical scavenging activity and ferric reducing ability power (43.04–48.87 g/100 g, 182.77–201.65   mmol TEAC/100 g and 613.29–637.81 mmol TE/100 g) than control (33.86 g/100 g, 109.43 mmol TEAC/100 g and 540.13 mmol TE/100 g). Springiness, cohesiveness and resilience values of wheat bread were not significantly different from composite bread. Scanning electron microscopy revealed that composite bread had surfaces with embedded granules like protein deposits with small spores.     

Extraction of alkylresorcinols from wheat bran with supercritical CO2

The supercritical fluid extraction (SFE) of wheat bran alkylresorcinols has been studied. Extractions were carried out at 40.0 MPa. The effect of particle size, static extraction pretreatment with supercritical CO₂ (SC-CO₂) and extraction temperature on the extraction kinetics was investigated. The extraction yield increased as the particle size decreased and with temperature. Extraction curves present a faster and linear initial extraction period followed by a slower extraction period. Based on these results the approximate mathematical model of Sovová was successfully applied to describe the extraction curves. The total content of alkylresorcinols was determined and compared with the alkylresorcinol content obtained by conventional organic solvent extraction. Due to the amphiphilic nature of these resorcinolic lipids, the extraction yield was higher for polar organic solvents than for SC-CO₂. Characterization of supercritical extracts was also performed by determining the fatty acid composition and antioxidant activity.     

Lycopene-rich fractions derived from pink guava by-product and their potential activity towards hydrogen peroxide-induced cellular and DNA damage

Effects of solvent and supercritical carbon dioxide (SC-CO₂) extraction on antioxidant and cytotoxic activities of lycopene-rich fractions of decanted pink guava by-product (decanter) were determined with lycopene-equivalent antioxidant capacity, β-carotene bleaching and MTT (3-(4,5-dimethylthiazol-2yl)-2,5-diphenyl tetrazolium bromide) assays. Extraction with SC-CO₂ gave a higher yield than solvent extraction (3.15 vs. 0.68 mg/100 g dried decanter, corresponding to 42.99 and 33.63 mg of lycopene). No cytotoxicity was found in Chang liver cells supplemented with either extracts (6.25–200 μg/ml). Solvent extract at 25 μg/ml (2.32 μM lycopene) and SC-CO₂ extract at 200 μg/ml (5.09 μM lycopene) had protective effect against hydrogen peroxide-induced cytotoxicity. However, only high concentrations of solvent extract (200 μg/ml; lycopene = 18.65 μM) or lycopene standard (10 μM) protected cells against DNA damage. Supercritical fluid extraction demonstrated a higher yield in lycopene-rich fraction from decanter. These fractions have the potential to be developed as a functional ingredient to prevent oxidative stress and other related diseases.     

Physicochemical characterisation of dietary fibre components and their ability to bind some process-induced mutagenic heterocyclic amines,Trp-P-1, Trp-P-2, AαC and MeAαC

The physicochemical properties of potato fibre, wheat bran and oat samples were investigated, along with their binding capability to heterocyclic amines (HCAs). Potato fibre displayed highest total dietary fibre content (71.8/100 g dry weight basis, dwb), followed by wheat bran (57.2/100 g dwb) and oat sample 2 (53.0/100 g dwb). Oat samples 1, 3 and 4 displayed considerably lower dietary fibre content (20.5–28.8/100 g, dwb). Oat samples 3 and 4 displayed highest soluble fibre content (70–83%), and oat sample 3 also displayed highest swelling and water retention capacity (WRC). Dietary fibre samples, except samples 3 and 4, displayed improved binding to HCAs as sample weight increased. The behaviour of wheat bran and potato fibre was similar to oat samples 1 and 2. Binding of MeAαC was comparatively greater than that of other HCAs. Dietary fibre fractions with high insoluble fibre and functional groups of HCAs may significantly contribute to the binding capacity.     

Characterization of supercritical fluid extrusion processed rice–soy crisps fortified with micronutrients and soy protein

Protein and micro-nutrients enriched rice–soy crisps (RSC) were prepared using supercritical fluid extrusion and their impact on quality attributes was determined. A low-shear, twin screw, co-rotating extruder was used to produce puffed RSC using supercritical CO₂ (SC-CO₂), which served as an expansion agent during the process carried out at lower temperatures (∼100 °C) compared to conventional steam based extrusion (∼130–180 °C). The fortified RSC contained 25–40 g/100 g soy protein and four micronutrients (iron, zinc, vitamin A and C) at the recommended daily values in 100 g product. The RSC were analyzed for physical characteristics and nutrient composition. The increasing soy protein fortification from 25 to 40 g/100 g reduced the crisps expansion ratio (4.27–2.95), crispiness (15.0–9.5), and increased piece density (0.21–0.27 g/cm³), bulk density (0.17–0.22 g/cm³) and hardness (76.39–129.05 N). The nutrient fortification improved protein (334–568%) and dietary fiber (571–901%) and the extrusion process retained all of the added minerals and about 50% retention of vitamin A and C in the final products. The SC-CO₂ assisted extrusion is an effective process-based approach to produce low-moisture, fortified crispy products. These products are appropriate for consumption as nutribars especially for school lunch programs in developing countries to reduce malnutrition through process based nutrient fortification approaches.     

Optimisation of ultrasound-assisted extraction of phenolic compounds from wheat bran

Wheat bran, an important by-product of the cereal industry, is rich in potentially health-promoting phenolic compounds. In this paper, the phenolic compounds from wheat bran were extracted by ultrasound-assisted extraction technology. The experiments were carried out according to a five level, three variable central composite rotatable design (CCRD), and the best possible combination of solvent concentration, extraction temperature and extraction time with the application of ultrasound, for maximum extraction of phenolic compounds from wheat bran, was obtained, through response surface methodology (RSM). The optimum extraction conditions were as follows: ethanol concentration, 64%; extraction temperature, 60 °C; and extraction time, 25 min; and the extraction time was the most significant parameter for the process. Under the above-mentioned conditions, the experimental total phenolic content was 3.12 mg gallic acid equivalents/g of wheat bran tested, which is well matched with the predicted content.     

Preparation of isoflavones enriched soy protein isolate from defatted soy hypocotyls by supercritical CO2

Soy hypocotyls, the byproduct from soy protein industry, rich in isoflavones, was attempted to develop into a value-added functional food, soy protein isolate (SPI). Soy hypocotyls were defatted by supercritical CO₂ (SC-CO₂) under the following conditions as 35 MPa, 2 h, 45 °C with a constant flow rate of CO₂ at 5 l/min, fed from the bottom of the extraction vessel. Via extraction, the oil contents were lowered from 10.5 g/100 g in original soy hypocotyls to 0.2 g/100 g in defatted soy hypocotyls (DSH) with a Protein Dispersibility Index (PDI) value of 91.2 that contained about 2.18 g/100 g of isoflavones and 63.6 g/100 g of proteins. SPI was then extracted from DSH under the optimized conditions including: the pH of water solution at 6, the ratio of DSH to water solution as 1:10 and the extraction temperature at 30 °C with the extraction time of 30 min. The freeze-dried SPI contained 92.46 g/100 g of the proteins and 640 mg/100 g of isoflavones, where the three major β-glycosides, glycitin, daidzin and genistin accounted for about 83.7% of the total isoflavones. The yields of SPI and isoflavones were about 48% and 30% in terms of their respective total contents in DSH.