Orange Pomace Research Articles

Toward Enhancing the Enzymatic Activity of a Novel Fungal Polygalacturonase for Food Industry: Optimization and Biochemical Analysis.

The review of literature and patents shows that enhancing the polygalacturonase (PG) production and activity are still required to fulfill the increasing demands. A dual optimization process, which involved Plackett-Burman design (PBD), with seven factors, and response surface methodology, was applied to optimize the production of extracellular PG enzyme produced by a novel strain of Aspergillus flavus isolated from rotten orange fruit. The fungal PG was purified and biochemically characterized. Three variables (harvesting time, pH and orange pomace concentration), that were verified to be significant by the PBD analysis, were comprehensively optimized via Box-Behnken design. According to this optimization, the highest PG activity (4073 U/mL) was obtained under pH 7 after 48 h using 40 g/L orange pomace as a substrate, with enhancement in PG activity by 51% compared to the first PBD optimization step. The specific activity of the purified PG was 1608 U/mg with polygalacturonic acid and its molecular weight was 55 kDa. The optimum pH was 5 with relative thermal stability (80%) at 50˚C after 30 min. The PG activity improved in the presence of Cu2+ and Ca2+, while Ba2+, Fe2+ and Zn2+ greatly inhibited the enzyme activity. The obvious Km and Vmax values were 0.8 mg/mL and 2000 μmol/min, respectively. This study is a starting point for initial research in the field of optimization and characterization of A. flavus PG. The statistical optimization of A. flavus PG and its biochemical characterization clearly revealed that this fungal strain can be a potential producer of PG which has a wide range of industrial applications.

Comparative evaluation of dry and wet carbonization of agro industrial wastes for the production of soil improver

This study examined the influence of process variables on the hydrochar production from wet biomasses and compared the agronomic value of hydrochars with that of the biochars produced by dry carbonization. Response surface methodology was used to investigate the effect of each three process variables (temperature, biomass:water ratio and reaction time) in hydrothermal carbonization (HTC) as well as their combined interactive effect on the mass yield and stable-C content of hydrochars. The results showed that the temperature and reaction time were significant factors affecting the stable-C content in HTC of the orange pomace, whereas the effect of all process variables is evident on stable-C content in HTC of grape pomace. For orange pomace, the effect of interaction between temperature and reaction time on mass yield was significant. However, in case of grape pomace, there existed no interaction effect between process variables on stable-C and mass yield.Findings from this work showed that char properties related to soil amendment are essentially determined by the type of carbonization process. Compared to the biochars produced by dry carbonization, the hydrochars had higher CEC and lower EC but more acidic pH values and lower stable-C content. Although chars have almost similar nitrogen content, the amount of water soluble nitrogen compounds in biochars were found to be significantly higher compared to the hydrochars. This result suggests that N-containing structures in the biomasses during HTC process were probably condensed to form N-heterocyclic aromatic structures, while much of nitrogen in biochars was present as available nitrate and amine N.

Studies on exploration of orange pomace powder on physical, sensorial and nutritional quality of biscuits

Studies on exploration of orange pomace powder on physical, sensorial and nutritional quality of biscuits

Production of pectinases for quality apple juice through fermentation of orange pomace.

Production of pectinases by Aspergillus niger was successfully carried out through solid state fermentation. Orange pomace was used as substrate to produce pectinases using a wild type of A. niger isolated from a rotten orange texture. Some of the important parameters affecting exo- and endo-pectinases activities such as temperature, moisture, C/N ratio were optimized. The results indicated that the produced pectinases exhibited maximum activity in temperature range of 45-55°C and the maximum enzyme productivity occurred at 70% moisture content and C/N ratio of 10. The enzyme kinetic was studied using Michaelis-Menten and Logistic model and the equation were fitted to experimental data for both exo- and endo-pectinases activities. In evaluation of kinetic model, it was found that Monod model presented perfectly fitted with experimental data. Monod kinetic parameters [Formula: see text] for exo-pectinase activities were [Formula: see text] mM, respectively. The Monod kinetic parameters [Formula: see text] for endo-pectinase activity were [Formula: see text] and [Formula: see text] respectively. Finally, the performances of the produced pectinases were evaluated on natural apple juice. It was confirmed that concentration of soluble sugar, clarity and viscosity of the juice and the yield of extracted juice were significantly improved by the enzymatic hydrolysis activity of pectinases.

Maximizing the Benefit of Orange Pomace

A study was carried out to maximize the benefits of orange pomace through different treatments including chopping process at different times (5, 10 and 15 s), pressing using a laboratory scale hydraulic press unit at four different levels of applied pressure (50, 100, 150 and 200 bar) for exposure times of (5, 10, 15 and 20 min) with pre-treatment of the samples using Ca(OH)2 in comparison with non-treated samples. Following this process, the most proper pressing treatment was assigned for a drying process using a conduction rotary heating unit at heating surface temperatures of (100, 110, 120, 130 and 140 oC) for drying times of (10, 20, 25, 30, 35 and 40 min). Two different drying models (Lewis model and Henderson & Pabis's model) were assigned for describing the drying data and predicting the change in orange pomace moisture content. Quality evaluation tests were also conducted for the dried samples including chemical composition, water retention capacity (WRC) and oil holding capacity (OHC). The results show that chopping process for 10s showed the highest extraction efficiency, the samples treated with Ca(OH)2 and pressed at 150 bar for 15 min recorded the lowest value of moisture content (105.46% d.b.). Meanwhile, the drying process at heating surface temperature of 110 oC for 40 min showed the lowest reduction in pomace quality. Also, Lewis model could describe the drying behavior of orange pomace satisfactory.

Characterization and physicochemical properties of pectins extracted from agroindustrial by-products

The composition and fine structure of pectins found in plant cell walls are heterogeneous, with striking differences, depending on their source, and this eventually determines their functional and technological properties. The aim of this study was to extract and determine the chemical composition and physicochemical properties of pectins from different sources: passion fruit peel, orange pomace, and soy hull. Pectin extraction was performed with heated hydrochloric acid solution, followed by precipitation with 96% ethanol. Extraction yield, chemical composition, molar mass, physicochemical properties (fat absorption capacity, cation exchange capacity, water holding capacity, and antioxidant activity) of pectin were measured. Pectin extraction efficiency was higher for passion fruit peel and orange pomace (15.71 and 17.96%, respectively). Soy hull had low pectin extraction (5.66%). Galacturonic acid content was 23.21% for passion fruit peel pectin and 16.01% for orange pomace pectin. Water holding capacity, fat absorption capacity, and cation-binding capacity present in pectin extracted from passion fruit peel were higher, suggesting this poorly investigated product could be used as thickening and emulsifying agents in food preparations. Phenolic compounds with antioxidant capacity provide pectins with additional properties and expand their industrial use.

Orange Pomace Improves Postprandial Glycemic Responses: An Acute, Randomized, Placebo-Controlled, Double-Blind, Crossover Trial in Overweight Men.

Orange pomace (OP), a fiber-rich byproduct of juice production, has the potential for being formulated into a variety of food products. We hypothesized that OP would diminish postprandial glycemic responses to a high carbohydrate/fat breakfast and lunch. We conducted an acute, randomized, placebo-controlled, double blind, crossover trial with 34 overweight men who consumed either a 255 g placebo (PLA), a low (35% OP (LOP)), or a high (77% (HOP)) dose OP beverage with breakfast. Blood was collected at 0, 10, 20, 30, and 45 min and at 1, 1.5, 2, 3, 4, 5, 5.5, 6, 6.5, 7, and 8 h. Lunch was consumed after the 5.5-h blood draw. OP delayed the time (Tmax1) to the maximum concentration (Cmax1) of serum glucose during the 2-h period post breakfast by ≥36% from 33 (PLA) to 45 (HOP) and 47 (LOP) min (p = 0.055 and 0.013, respectively). OP decreased post-breakfast insulin Cmax1 by ≥10% and LOP delayed the Tmax1 by 14 min, compared to PLA at 46 min (p ≤ 0.05). HOP reduced the first 2-h insulin area under concentration time curve (AUC) by 23% compared to PLA. Thus, OP diminishes postprandial glycemic responses to a high carbohydrate/fat breakfast and the second meal in overweight men.

Studies on effect of orange (Citrus sinensis) pomace powder on physical, chemical and nutritional quality attributes of cake

Studies were conducted for incorporation of orange pomace powder in cake. The orange pomace powder was used in various proportion viz ., 0, 5, 10, 15 and 20 per cent levels for incorporation in cake by replacing the maida. The orange pomace powder and maida was analyzed for the proximate composition. The cakes were prepared and were analyzed for its physical (specific volume, volume and weight), chemical (moisture, protein, fat, ash, fibre) and sensorial characteristics (appearance, colour, flavour, taste, texture). On the basis of overall sensory attributes, cakes prepared with 10 per cent of orange pomace powder were recorded higher acceptability as compared to other samples. The increase in powder concentration, the protein and fat content was decreased while the dietary fibre was increased. It was concluded that orange pomace powder and refined wheat flour can be substituted upto 10 per cent in refined wheat flour to prepare orange pomace powder without adversely affecting quality attributes.

Studies on exploration of orange pomace powder on physical, sensorial and nutritional quality of cookies

Processing of fruit and vegetable produces large quantity of waste particularly citrus processing produces waste in the form of peel, seeds and pomace which can be the major source of phyto-chemicals and dietary fibres. The objective of the research was to utilize the orange pomace in the form of powder in baked item. The orange pomace powder was used in various proportion viz. , 0, 5, 10, 15 and 20 per cent levels for incorporation in cookies by replacing the maida. The orange pomace powder and maida were analyzed for the proximate composition. The cookies were prepared and analyzed for its physical (diameter, thickness, and spread ratio), chemical (moisture, protein, fat, ash, fibre) and sensorial characteristics (appearance, colour, flavour, taste, texture). On the basis of overall sensory attributes cookies prepared with 10 per cent of orange pomace powder was recorded higher acceptability as compared to other samples. The spread ratio of the cookies also decreased as the per cent of orange pomace powder was increased with the increase in powder concentration the protein, fat content was gradually, decreasing and the dietary fibre. Orange pomace powder can be substituted upto 10 per cent in wheat flour to prepare orange pomace powder cookies without adversely affecting overall quality attributes.

Effects of spent liquor recirculation in hydrothermal carbonization

In this study, the effect of the recirculation of spent liquor from hydrothermal carbonization was investigated depending on the biomass type (grape pomace, orange pomace and poultry litter). The yield and fuel properties of hydrochars and spent liquor characteristics were determined for each recirculation step. By recirculation, mass and energy yields of the hydrochar increased, but their combustion characteristics changed: the ignition temperature and combustion reactivity decreased. The organic and inorganic load of liquor was increased with recirculation number, but not as much as would be expected after the first recycle. It was concluded that the load of organic and inorganic species in spent liquor decreased the leaching of some inorganics and diffusion of the degraded soluble fragments from biomass in the subsequent hydrothermal carbonization. Overall, this study showed that spent liquor recirculation makes the overall hydrothermal carbonization process environmentally friendly.

Extraction of phenolic compounds from dry and fermented orange pomace using supercritical CO2 and cosolvents

This work investigated the supercritical fluid extraction (SFE) of phenolic compounds from the pomace generated in the industrial processing of orange (Citrus sinensis) juice in Brazil. The effect of the biotransformation of the pomace, performed through solid-state fermentation using Paecilomyces variotii, in the phenolic content and antioxidant activity of the extracts was also evaluated. SFE was carried out at pressures of 15, 25 and 35MPa and temperatures of 40, 50 and 60°C, using pure ethanol and ethanol:water (9:1 v/v) as cosolvents. The extracts were evaluated in terms of global extraction yield, total phenolic content (TPC), phenolic profile by HPLC, and antioxidant activity through DPPH and ORAC assays. Additionally, a low pressure extraction was performed (Soxhlet) for comparison to SFE, using ethanol as solvent. The results of SFE showed that high pressures improved the global extraction yield, which ranged from 2.01 to 2.62%, and TPC (18–21.8mgGAE/g dry extract). Nevertheless, the increase of pressure decreased the antioxidant activity of the extracts. The use of ethanol 90% as cosolvent enhanced the extraction of antioxidant compounds. The biotransformation process improved the TPC and provided extracts with higher antioxidant activities by both DPPH and ORAC assays.

Orange pomace fibre increases a composite scoring of subjective ratings of hunger and fullness in healthy adults

Dietary fibre has been shown to increase subjective satiating ratings. However data from human trials has produced mixed results, possibly due to different types of fibre which have diverse physicochemical properties and gastrointestinal transit behaviour. The aim of study 1 was to investigate whether orange juice (OJ) with 5.5 g of added orange pomace fibre (OPF) was as satiating as whole orange (WO, chopped and blended to a puree/liquid) compared with OJ. Study 2 was to evaluate the dose-dependent satiating effect of OPF delivered in an orange-flavoured beverage. Both studies were randomized, controlled, double blind, cross over in design with 4 intervention arms in study 1 including OJ, OPF, WO, and water, and 3 arms in study 2: orange-flavoured beverage with low (2.5 g) and high (5.5 g) dose of OPF (LD-OPF and HD-OPF), and orange-flavoured beverage without fibre (Control). Volunteers were asked to response to 8 questions relating to hunger, fullness, desire to eat, thirst and discomfort by visual analogue scale (VAS) for each question. Differences were detected in least squares mean estimates of composite satiety scores and each individual question with statistical modelling to adjust for differences in baseline scores. Addition of 5.5 g OPF either to OJ or to orange-flavoured beverage significantly increased the composite satiety scores compared with OJ (P < 0.0001) or Control (P < 0.0001), and the effect was comparative to WO. LD-OPF showed some satiating effect (less desire to eat) compared with Control (P = 0.038), though less effective than HD-OPF (P = 0.043). In conclusion, the addition of OPF to OJ was as effective at increasing satiety as WO consumption compared with OJ; and there was a trend of dose-dependent effect of OPF on satiety compared with the control.

Addition of Orange Pomace to Orange Juice Attenuates the Increases in Peak Glucose and Insulin Concentrations after Sequential Meal Ingestion in Men with Elevated Cardiometabolic Risk

Background: Prospective cohort studies show that higher dietary fiber intake is associated with reduced cardiovascular disease risk, yet the impact on postprandial glucose and insulin responses is unclear.Objective: This study aims to evaluate the effects of orange beverages with differing fiber concentrations on postprandial glycemic responses (secondary outcome measure) after a sequential breakfast and lunch challenge in men with increased cardiometabolic risk.Methods: Thirty-six men (aged 30–65 y; body mass index 25–30 kg/m2: fasting triacylglycerol or total cholesterol concentrations: 0.8–2.2 or 6.0–8.0 mmol/L, respectively) were provided with a high-fat mixed breakfast and were randomly assigned to consume 240 mL Tropicana (PepsiCo, Inc.) pure premium orange juice without pulp (OJ), OJ with 5.5 g added orange pomace fiber (OPF), juice made from lightly blended whole orange, or an isocaloric sugar-matched control (Control) on 4 occasions separated by 2 wk. A medium-fat mixed lunch was provided at 330 min. Blood samples were collected before breakfast and on 11 subsequent occasions for 420 min (3 time points postlunch) to determine postprandial glucose, insulin, lipid, and inflammatory biomarker responses. Repeated-measures ANOVA was used for data analysis.Results: OPF significantly (P < 0.05) reduced the maximal change in glucose concentrations (1.9 ± 0.21 mmol/L) reached after breakfast compared with other treatments (2.3–2.4 mmol/L) and after lunch (3.0 ± 0.05 mmol/L) compared with OJ (3.6 ± 0.05 mmol/L). The maximal change in insulin concentration (313 ± 25 pmol/L) was also lower compared with Control (387 ± 30 pmol/L) and OJ (418 ± 39 pmol/L) after breakfast. OPF significantly delayed the time to reach the peak glucose concentration compared with Control and OJ, and of insulin compared with Control after breakfast.Conclusion: OPF consumed with breakfast may lower postprandial glycemic and insulinemic responses to typical meal ingestion in men with increased cardiometabolic risk. This trial is registered at http://clinicaltrials.gov as NCT01963416.

Effects of feedstock type and pyrolysis temperature on potential applications of biochar

In this study, the effect of feedstock type and pyrolysis temperature on the properties of biochar samples relating to their utilization as energy feedstock and soil amendment was investigated. For this purpose, four different types of biomasses (vine pruning (VP), poultry litter (PL), orange pomace (OP) and seaweed (AB)) were pyrolyzed at different temperatures between 250 and 600°C. The pyrolysis temperature of 350°C was found as critical upper temperature in the production of biochar used as fuel. The VP and OP were seen to be more suitable than PL and AB for solid fuel production. The stable carbon contents of biochars produced at 500°C and 600°C were over than 98%. With increasing of pyrolysis temperature, plant nutrients (except K) in biochars become less available to plants. Although the carbon exchange capacity was the highest in AB and PL biochars, they had extremely high electrical conductivity values.

Acute orange pomace consumption diminishes postprandial glycemic responses in healthy men

Orange pomace (OP) is an edible part of waste streams generated from juice processing. It can be a high potential nutrient source. We hypothesized that OP would diminish postprandial glycemic responses to a high carbohydrate/fat breakfast and lunch. We conducted an acute, randomized, placebo controlled, double blind, crossover trial with 34 healthy men (52.1 ± 7.7 y; BMI, 27.7 ± 1.5 kg/m2). Subjects were randomized to consume 255 g placebo (PL), low [(35% OP) LOP] and high [(77%) HOP] dose OP beverage with breakfast (51 g fat, 64 g CHO, 777 kcal). Blood was collected at 0, 0.17, 0.34, 0.5, 0.75, 1, 1.5, 2, 3, 4, 5, 5.5, 6, 6.5, 7, and 8 h. Lunch (30 g fat, 60 g CHO, 628 kcal) was consumed after the 5.5-h blood draw. OP delayed the time (Tmax) to the maximum concentration (Cmax) of blood glucose during the 2-h period post breakfast by ≥36% from 33 (PL) to 45 (HOP) and 47 (LOP) min (P = 0.055 and 0.013, respectively) while the Cmax was not altered. OP did not modify the overall area under time curve (AUC) of blood glucose though values were lower in most periods after the HOP. OP decreased post-breakfast insulin Cmax by ≥10% in a dose-dependent manner and LOP delayed the Tmax by 14 min vs. PL at 46 min (P ≤0.05). HOP reduced the first 2-h insulin AUC by 23% vs. PL and tended to decrease the overall AUC. Thus, OP diminishes postprandial glycemic responses to a high carbohydrate/fat breakfast and lunch in a dose-dependent manner and may enhance insulin efficacy. Support or Funding Information USDA & PepsiCo Postprandial insulin kinetics Postprandial glucose kinetics

The effect of extrusion processing on the physiochemical properties of extruded orange pomace

Soluble dietary fibre (SDF) is considered the most effective fraction of dietary fibre (DF) for human health. In this study, extrusion technology was applied to enhance the SDF obtained from orange pomace, a byproduct of juice extraction containing a high level of DF. The pomace was processed in a single-screw extruder at various barrel temperatures (X1; 115–135°C), feed moistures (X2; 10–18g/100g), and screw speeds (X3; 230–350rpm). Based on response surface methodology, the optimum extrusion conditions, which produced a maximum SDF value of 30.36%, were as follows: barrel temperature, 129°C; feed moisture, 15%; and screw speed, 299rpm. Compared with unextruded pomace, SDF fraction in extrudate had a higher level of uronic acid. Furthermore, the extrusion process improved the physicochemical properties of extrudate, increasing the water-holding capacity, swelling, water solubility index, and cation-exchange capacity and decreasing the oil-holding capacity.

Characterization of products from hydrothermal carbonization of orange pomace including anaerobic digestibility of process liquor

In this study, the effect of the temperature and reaction time on hydrothermal carbonization (HTC) of orange pomace was investigated. In addition, a set of anaerobic batch tests were performed to determine the resulting biogas and methane potential of the spent liquor. Hydrochar yields followed a decreasing trend with the increasing temperature, whereas reaction time had no considerably effect on the yield. The evolution of the H/C and O/C atomic ratios from the raw material to the hydrochars suggested that dehydration reactions prevail during HTC. The hydrochars tended to become enriched in Ca, Mg and P minerals by increasing HTC temperature. The heavy metal contents in hydrochars were found below limits and no PAH compound was detected. Anaerobic digestion tests showed that the aqueous phase from HTC can be used as feedstocks for biogas production.

Physicochemical assessment of two fruit by-products as functional ingredients: Apple and orange pomace

The purpose of this study was to evaluate the properties of two fruit by-products (apple pomace from the Cv. “Karmijn de Sonnaville” and orange pomace from the Cv. “Valencia”) as potential ingredients. The analysis comprised: microstructure, composition, physicochemical properties, pectin quantity and gelling properties of the two materials.Studying both orange pomace and apple pomace highlighted the different aspects of the two materials orange pomace was mainly fibrous ingredient with applications suited to products requiring improved water/oil holding and binding properties ie. a high water hydration capacity (4.40ml/g). It had a favourable nutritional composition: high dietary fibre (40.47%), low fat (2.14%) and a high mineral content. In comparison, apple pomace showed visco-elastic properties that could enhance structures within products. Oscillatory rheology illustrated pastes from apple pomace had a high storage modulus (G′). Due to its pectin and starch content, apple pomace flour formed viscous pastes and visco-elastic structures. This study illustrates the importance of comprehending individual components (physicochemical and nutritional) of ingredients to fully utilise their activity in a food system.

Physicochemical properties of modified citrus pectins extracted from orange pomace.

Modified pectin is a polysaccharide rich in galacturonic acid altered by pH adjustment and thermal treatment used especially as an anti-cancer agent. The aim of this work was to study the physical and chemical properties of modified pectins extracted from orange pomace with citric and nitric acids. The galacturonic acid content, degree of esterification, Fourier Transform Infrared Spectroscopy profile, molecular weight, intrinsic viscosity, rheological properties and antioxidant activity of the pectins were evaluated. The modification process caused the de-esterification of pectins and a decrease of molecular weight due to removal of neutral sugars, maintaining the linear chain of galacturonic acid. Such changes also caused a significant increase in the in vitro antioxidant activity (p ≤ 0.05) and influenced the rheological properties of pectin, reducing its viscosity. This work showed that the modification of pectin from orange pomace with citric and nitric acids altered its structural and physical characteristics as well as its biological activity toward a free-radical.

Modelling the effects of orange pomace using response surface design for gluten-free bread baking

The development of gluten-free bread creates many challenges; producing bread that will match the properties of its wheat counterpart can be difficult. Fruit by-products are know from literature to contain a high level of dietary fibre which could improve the bread properties and fibre contents of gluten-free bread.Therefore, a mathematical design was created; three variables were identified from preliminary tests (water (85–100% flour weight, OP 0–8% flour weight and proofing time 35–100min) as being crucial in the development of acceptable bread.Results illustrated longer proofing times (p<0.05) and lower orange pomace levels (OP) (p<0.001) produced a bread with a greater specific volume. OP had the most significant (p<0.0001) effect on hardness at 2h and 24h post-baking. The optimised formulation was calculated to contain 5.5% OP, 94.6% water and a proofing time of 49min. Total fibre content of the control bread (2.1%) was successfully increased to 3.9% in the OP containing bread. Substituting gluten-free flours with orange pomace flour can help improve the total dietary intake of a coeliac while not negating on the quality properties of the bread.