Sunflower Head Residues Research Articles

Determining the Ruminal Degradability of Sunflower Head Residues and the Effect of its Different Levels on Digestibility, Blood Parameters and Chewing Activity of Fattening Afshari Lambs

Determining the Ruminal Degradability of Sunflower Head Residues and the Effect of its Different Levels on Digestibility, Blood Parameters and Chewing Activity of Fattening Afshari Lambs

Biogas Production from Sunflower Head and Stalk Residues: Effect of Alkaline Pretreatment

Sunflower residues are considered a prominent renewable source for biogas production during anaerobic digestion (AD). However; the recalcitrant structure of this lignocellulosic substrate requires a pretreatment step for efficient biomass transformation and increased bioenergy output. The aim of the present study was to assess the effect of alkaline pretreatment of various parts of the sunflower residues (e.g., heads and stalks) on their methane yield. Experimental data showed that pretreatment at mild conditions (55 °C; 24 h; 4 g NaOH 100 g−1 total solids) caused an increase in the biochemical methane potential (BMP) of both heads and stalks of the sunflower residues as determined in batch tests. The highest methane production (268.35 ± 0.11 mL CH4 g−1 volatile solids) was achieved from the pretreated sunflower head residues. Thereafter; the effect of alkaline pretreatment of sunflower head residues was assessed in continuous mode; using continuous stirred-tank reactors (CSTRs) under two operational phases. During the first phase; the CSTRs were fed with the liquid fraction produced from the pretreatment of sunflower heads. During the second phase; the CSTRs were fed with the whole slurry resulting from the pretreatment of sunflower heads (i.e., both liquid and solid fractions). In both operating phases; it was observed that the alkaline pretreatment of the sunflower head residues had a negligible (phase I) or even a negative effect on biogas production; which was contradictory to the results of the BMP tests. It seems that; during alkaline pretreatment; this part of the sunflower residues (heads) may release inhibitory compounds; which induce a negative effect on biogas production in the long term (e.g., during continuously run digesters such as CSTR) but not in the short-term (e.g., batch tests) where the effect of the inoculum may not permit the inhibition to be established.

Compositional changes in lignocellulosic content of some agro-wastes during the production cycle of shiitake mushroom

The study assessed the changes in digestibility of some agricultural wastes such as chickpea straw (CPS), corn stalk (CS), alfalfa hay (AH) and sunflower head residue (SFH) during the spawn running period and fruitbody production of Lentinula edodes (Berk.) Pegler (shiitake) to better understand the nutritional needs of this mushroom species. In addition, the effects of these wastes on some productivity features of shiitake cultivated under laboratory conditions were evaluated. Oak awdust (OS) was used as a control substrate. The substrates were analyzed for nitrogen (N), cellulose, hemicellulose and lignin content at three different growth stages. Morever, the effect of agro-wastes on spawn run time, time to first primordia initiation, time to first harvest, yield, biological efficiency (BE) and average mushroom weight were evaluated during the cultivation cycle. Among the five substrates, the SFH exhibited maximum productivity, followed by CPS (233.7 g/kg and 228.1 g/kg, respectively). No correlation was found between the shiitake yield and the N or lignocellulosic content of the growing substrates. On the other hand, the shiitake consumed hemicellulose during the spawn running period, whereas the consumption of cellulose and lignin occured during the pinheading and fruiting formation stages. The hemicellulose, cellulose and lignin contents in the spent substrate were 36.5–51.9%, 5.3–27.0% and 24.0–36.8% lower, respectively, than in the initial substrates, while the N content in the mushroom substrate was increased by 10.3% (CS)−97.1% (OS) after shiitake cultivation. In conclusion, shiitake mushrooms had a preference for substrates containing a moderate amount of N, hemicellulose and lignin, and having a low cellulose:lignin ratio. Morever, the chemical composition of the growing substrates changed during the life cycle of the mushroom and the protein content increased with time, while the amount of lignocellulosic content in the substrates was reduced, making it more digestible.

Value Added Products from Plant Processing

Fat and wax (F&W) compounds have to be removed from raw plant materials before pectin and oligosaccharides (OS) can be isolated. In this research, the mixtures of F&W, and polyphenols and sugars were firstly separated from the roots of Eremurus hissaricus (Eremurus h.), and the byproducts of fruit processing, such as apple pomace, sunflower head residues, and grape seeds, etc., using hexane/ethanol or ethyl acetate as leaching reagents at various ratios of liquid to solid. The resultant mixtures were then extracted with an ethanol/water mixture to separate F&W from polyphenols and sugars. It was found that the F&W yield decreased in the sequence of apricot > apple > sunflower head residues > peach > pumpkin with 21.84% in apricot as the highest number. The amount of alcohol-water soluble compounds (AWSC), mainly polyphenols and sugars, decreased in the sequence of peach > sunflower head residues > apricot > pumpkin > apple. No inter-dependence of AWSC and F&W was identified.

Properties of poly(butylene adipate‐co‐terephthalate) and sunflower head residue biocomposites

ABSTRACTUtilization of low‐value agricultural waste for polymer composite materials has great environmental and economical benefits. Sunflower head residue (SHR) as an agricultural waste may be used as a reinforcement in polymeric materials because of its fiber characteristics. In this work, composites of biodegradable poly(butylene adipate‐co‐terephthalate) (PBAT) and SHR were prepared via melt‐extrusion compounding. To improve interfacial compatibility, maleic anhydride (MA) grafted PBAT (PBAT‐g‐MA) was prepared and used as a compatibilizer for the PBAT/SHR composites. The effects of the concentrations of SHR and PBAT‐g‐MA on the morphology, mechanical properties, melt rheology, and water resistance of the composites were examined. Interfacial adhesion between phases in the PBAT/SHR composites was enhanced by the introduction PBAT‐g‐MA as interface‐strengthening agent, resulting in improved mechanical properties and moisture resistance of the composite. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 44644.

Extraction and characterization of sunflower pectin

Chemical composition and rheological properties of sunflower pectin, including gel-point temperature ( T g) were determined. Pectin from sunflower head residues was characterized and compared with low methoxyl commercial pectins. Pectin was isolated using sodium hexametaphosphate extraction followed by either acidified alcohol (KIM) or HCl solution (LIN) precipitation. LIN pectin resulted with a higher ash content (≈30%).The low methoxyl pectin extracted from sunflower heads had 11% degree of esterification, high anhydrogalacturonic acid content (77–85%) and low acetyl content (2.3–2.6%) on an ash-free basis. Viscosity average molecular weight ranged from 39,500 to 52,000. Sunflower pectin formed gels at high temperatures almost instantly in the presence of calcium ions.

Galacturonic acid in pectic substances of sunflower head residues: quantitative determination by HPLC

Assuming the interest in low-methoxyl pectin from sunflower head residues lies mainly in the production of low-caloric foods a precise and fast method for the quantification of galacturonic acid would be helpful. An HPLC method involving enzymatic hydrolysis was compared with colorimetric and titrimetric procedures. The results showed that the quantitative data obtained by HPLC method (96.5%) were in good agreement with those from other methods (97.0 and 92.9%, respectively). Because the colorimetric analysis is expensive and highly time consuming and titrimetric procedure demands an accurate purification of the pectin, the HPLC method applied in this study proved to be useful for the galacturonic acid quantification.

Sunflower Head Residue Pectin Extraction as Affected by Physical Conditions

ABSTRACTEffects of extraction pH, temperature, and time on yield and quality of pectin from sunflower heads (Interstate cultivar) were investigated. The low‐methoxyl pectin was extracted, using 0.75% sodium hexametaphosphate at pH 3, 4, and 5 and at 75, 85, and 95°for 20, 40, and 60 min, respectively. Yield, molecular mass, and firmness of jellies of the pectins were determined. Three‐way statistical analysis on yield, molecular mass and gel firmness showed strong interactions among pH, temperature and time. Highest yields were obtained at pH 5, 95°for 20 min and pH 4, 85°for 40 min. Pectin extracted for 40 min at pH 3 and 4 and at 85°and 75°C, respectively, had the highest molecular mass. Gel firmness of sunflower pectin prepared at pH 5.4 was higher than that of a commercial citrus pectin.

Cultivar/Location and Processing Methods Affect Yield and Quality of Sunflower Pectin

ABSTRACTThe influence of cultivar/location of sunflower and grinding, blanching, water washing, and re‐extraction of sunflower head residues were studied for yield and quality of pectin. Sunflower head residues from seven varieties/locations were used. The Interstate cultivar from Ardock (North Dakota) and Agri‐Pro from Canington (North Dakota) had highest yields (9.14–9.47%). Galacturonic acid content of the pectin did not differ significantly among cultivars. Grinding sunflower heads to particle size <60 mesh did not increase yield or quality of pectin. Peroxidase in head residues was completely inactivated after heat treatment at 75°C for 15 min. Higher shear blending did not increase yield, but decreased molecular mass and firmness of pectin gels. Extracting pectin twice yielded a total 13–14% pectin without lowering pectin quality.

Extraction and Physicochemical Characterization of Pectin from Sunflower Head Residues

ABSTRACTPectin was isolated from sunflower head residues, using 0.75% sodium hexametaphosphate extraction followed by acid precipitation. The yield of pectin was7.3% of the head residues. The isolated pectin contained 89.2% anhydrogalacturonic acid, 2% acetyl ester, and 4.2% neutral sugars, which were mainly rhamnose and glucose. The degree of methylation was 38.5%. The pectin had a high viscosity (527 cp at 1% level) at pH 3 and a high water‐holding capacity (57g water/g organic matter). The peak molecular mass of the sunflower pectin was > 523,000 daltons.

Gelling Characteristics of Pectin From Sunflower Head Residues

ABSTRACTGelling properties of sunflower head pectin were studied using two instrumental methods: the standard sag method and the Instron textural profile method. For the Instron method, the jellies were formulated with 0‐60% sugar content with various amounts of calcium chloride (30 to 90 mg/g pectin) at pHs 5.4 and 6.0. Sunflower pectin had a gel power of 110 compared to 100 for a citrus low‐methoxyl pectin and 120 for an amidated low‐methoxyl pectin. Sunflower pectin formed jellies under all experimental conditions. Sunflower pectin has a high potential for producing low‐caloric foods, particularly when a near‐neutral taste is required.