Improvement of oxidative stability and textural properties of fermented sausage via addition of pistachio hull extract.
The purpose of this study was to evaluate the effectiveness of pistachio hull extract (PHE) as an antioxidant and antimicrobial agent for preservation of dry fermented sausages during fermentation and storage period. Sausages were prepared using starter culture (Biobak K) and treated with three levels of PHE (500, 750 and 1,000 ppm). The results showed that PHE at concentrations of 500 ppm and 750 ppm decreased significantly (p < .05) the TBARS content of the sausage samples compared to control (without PHE). Moreover, PHE increased L* and a* value of samples during fermentation period but did not affect the color of samples during storage period. The PHE was also able to improve the chewiness and gumminess of the fermented sausage. Evaluation of microbial properties (total viable count, yeast and molds, lactic acid bacteria, staphylococci and Enterobacteriaceae) also showed that antimicrobial activity of PHE in fermented sausage.
Antioxidant Properties of Agri-food Byproducts| and Specific Boosting Effects of Hydrolytic Treatments.
Largely produced agri-food byproducts represent a sustainable and easily available source of phenolic compounds, such as lignins and tannins, endowed with potent antioxidant properties. We report herein the characterization of the antioxidant properties of nine plant-derived byproducts. 2,2-Diphenyl-1-picrylhydrazyl (DPPH) and ferric reducing/antioxidant power (FRAP) assays indicated the superior activity of pomegranate peels and seeds, grape pomace and pecan nut shell. An increase in the antioxidant potency was observed for most of the waste materials following a hydrolytic treatment, with the exception of the condensed tannin-rich pecan nut shell and grape pomace. UV-Vis and HPLC investigation of the soluble fractions coupled with the results from IR analysis and chemical degradation approaches on the whole materials allowed to conclude that the improvement of the antioxidant properties was due not only to removal of non-active components (mainly carbohydrates), but also to structural modifications of the phenolic compounds. Parallel experiments run on natural and bioinspired model phenolic polymers suggested that these structural modifications positively impacted on the antioxidant properties of lignins and hydrolyzable tannins, whereas significant degradation of condensed tannin moieties occurred, likely responsible for the lowering of the reducing power observed for grape pomace and pecan nut shell. These results open new perspectives toward the exploitation and manipulation of agri-food byproducts for application as antioxidant additives in functional materials.
The Equilibrium, Kinetics, and Thermodynamics Studies of the Sorption of Methylene Blue from Aqueous Solution Using Pulverized Raw Macadamia Nut Shells.
In this study, the potential for pulverized raw macadamia nut shell (MNS) for the sequestration of methylene blue from aqueous media was assessed. The sorbent was characterized using scanning electron microscopy for surface morphology, functional group analysis was performed with a Fourier-transform infrared spectrometer (FT-IR), and Brunauer-Emmett-Teller (BET) isotherm was used for surface area elucidation. The effects of contact time, sorbent dosage, particle size, pH, and change in a solution matrix were studied. Equilibrium data were fitted using Temkin, Langmuir, and Freundlich adsorption isotherm models. The sorption kinetics was studied using the Lagergren pseudo-first-order, pseudo-second-order, Elovich, and intraparticle diffusion models. The feasibility of the study was established from the thermodynamic studies. A surface area of 2.763 m2/g was obtained. The equilibrium and kinetics of sorption was best described by the Langmuir and the pseudo-second-order models, respectively. The sorption process was spontaneous (-ΔG 0=28.72 - 31.77 kJ/mol) and endothermic in nature (ΔH 0=17.45 kJ/mol). The positive value of ΔS0 (0.15 kJ/molK) implies increased randomness of the sorbate molecules at the surface of the sorbent. This study presents sustainable management of wastewater using MNS as a potential low-cost sorbent for dye decontamination from aqueous solution.
Almond byproduct composition impacts the rearing of black soldier fly larvae and quality of the spent substrate as a soil amendment.
Background: Insect biomass is a sustainable alternative to traditional animal feeds, particularly when insects are produced on low-value high-volume agricultural by-products. Seven samples of almond by-product (hulls and shells) were obtained from processors in California and investigated for larvae production. Experiments were completed with and without larvae and spent substrate samples were assessed for their potential as soil amendments based on standard compost quality indicators. Results: On average, specific larvae growth and average larval harvest weight were 158% and 109% higher, respectively, when larvae were reared on Monterey and pollinator hulls compared to nonpareil hulls and mixed shells. Larvae methionine and cystine contents were highest when larvae were reared on Monterey hulls and mixed shells, respectively. Available phytonutrients in spent substrate were affected by feedstock sample and larvae rearing. Spent nonpareil substrate without larvae had the highest NH4 -N levels and spent pollinator substrate incubated without larvae had the highest PO4 -P levels. Spent mixed shell substrate had the lowest availability of phytonutrients. Conclusion: The findings demonstrate that by-product composition has a significant impact on larvae growth and the properties of the spent substrate, and that spent substrate from larvae rearing requires further stabilization before application as a soil amendment.
Removal of hydrogen sulfide from biogas using activated carbon synthesized from different locally available biomass wastes-a case study from Palestine.
The main aim of this study was to remove hydrogen sulfide (H2S) from biogas by adsorption using synthesized activated carbon prepared using locally available biomass. The effect of the type of precursors, impregnation reagent and bed height was studied in continuous reactors. Three types of biomass wastes (almond shells, eucalyptus and coffee grains) were collected, grinded, sieved, pyrolyzed at 500°C and impregnated with chemical reagents such as potassium hydroxide or zinc chloride. Adsorption tests were performed using a fixed bed filter filled with the produced activated carbon. The highest biochar yield of 36% was obtained eucalyptus followed by almond shells (28.5%) and coffee grains (24%), respectively. The highest adsorption capacity and removal efficiency were obtained with eucalyptus followed by almond shells and coffee grains, respectively. For instance, eucalyptus showed an adsorption capacity of ~690 (mg hydrogen sulfide/g adsorbent) followed by almond (230 mg hydrogen sulfide/g adsorbent) and coffee grains (22 mg hydrogen sulfide/g adsorbent). As an impregnation reagent, potassium hydroxide gave the highest adsorption efficiency and capacity than zinc chloride. Furthermore, the breakthrough time with KOH (180 min) was higher than ZnCl2 (70 min). Increasing the bed height during continuous breakthrough tests increased the adsorption capacity and hydrogen sulfide removal efficiency. The results of this study showed that the adsorption efficiency of the synthesized activated carbon and consequently the hydrogen sulfide removal efficiency could be fine-tuned by selecting an appropriate biomass precursor and proper impregnation reagent.
Turrón Coproducts as Source of Bioactive Compounds: Assessment of Chemical, Physico-Chemical, Techno-Functional and Antioxidant Properties.
The goals of this research were determined the proximate composition, physico-chemical, techno-functional properties, the polyphenolic profile, the organic acids and sugar content and the antioxidant capacities of flours obtained from almonds skins var. comuna (ASFC) and var. fritz (ASFF) coproducts produced in Turrón industry. The chemical composition and physico-chemical properties (pH, water activity and color) were determined. The water holding, oil holding and swelling capacities were also determined, as well as the polyphenolic profile. For the antioxidant capacity, four different assays were used namely: 2,2-diphenyl-1-picrylhydrazyl radical scavenging assay (DPPH•); Ferrous ions chelating activity (FIC); Ferric reducing antioxidant power (FRAP) and 2,2'-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid) radical scavenging assay (ABTS•+). The flours obtained from ASFC and ASFF had a high content of dietary fiber (70.50 and 69.83 g/100 g, respectively). The polyphenolic profile, determined by High Performance Liquid Chromatography, identified 21 and 19 polyphenolic compounds in both ASFC and ASFF, being epicatechin and catechin the most abundant compounds. In reference to the antioxidant capacity regards, with all methods assayed except FRAP, ASFC had higher antioxidant activity than ASFF. These coproducts show good technological and antioxidant properties, which makes them a good alternative for its use in the development of new foods.
Almond Skin Extracts and Chlorogenic Acid Delay Chronological Aging and Enhanced Oxidative Stress Response in Yeast.
Almond (Prunus dulcis (Mill.) D.A.Webb) is one of the largest nut crops in the world. Recently, phenolic compounds, mostly stored in almond skin, have been associated with much of the health-promoting behavior associated with their intake. The almond skin enriched fraction obtained from cold-pressed oil residues of the endemic Moroccan Beldi ecotypes is particularly rich in chlorogenic acid. In this study, both almond skin extract (AE) and chlorogenic acid (CHL) supplements, similar to traditional positive control resveratrol, significantly increased the chronological life-span of yeast compared to the untreated group. Our results showed that AE and CHL significantly reduced the production of reactive oxygen and nitrogen species (ROS/RNS), most likely due to their ability to maintain mitochondrial function during aging, as indicated by the maintenance of normal mitochondrial membrane potential in treated groups. This may be associated with the observed activation of the anti-oxidative stress response in treated yeast, which results in activation at both gene expression and enzymatic activity levels for SOD2 and SIR2, the latter being an upstream inducer of SOD2 expression. Interestingly, the differential gene expression induction of mitochondrial SOD2 gene at the expense of the cytosolic SOD1 gene confirms the key role of mitochondrial function in this regulation. Furthermore, AE and CHL have contributed to the survival of yeast under UV-C-induced oxidative stress, by reducing the development of ROS/RNS, resulting in a significant reduction in cellular oxidative damage, as evidenced by decreased membrane lipid peroxidation, protein carbonyl content and 8-oxo-guanine formation in DNA. Together, these results demonstrate the interest of AE and CHL as new regulators in the chronological life-span and control of the oxidative stress response of yeast.
Solid state 13C-NMR methodology for the cellulose composition studies of the shells of Prunus dulcis and their derived cellulosic materials.
Lignocellulosic fibers and microcellulose have been obtained by simple alkaline treatment from softwood almond shells. In particular, the Prunus dulcis Miller (D.A.) Webb. was considered as a agro industrial waste largely available in southern Italy. The materials before and after purification have been characterized by 13C CPMAS NMR spectroscopy methodology. A proper data analysis provided the relative composition of lignin and holocellulose at each purification step and the results were compared with thermogravimetric analysis and FT-IR. To value the possibility of using this material in a circular economy framework, the fibrous cellulosic material was used to manufacture a handmade cardboard. The tensile performances on the prepared cardboard proved its suitability for packaging purposes as a sustainable material. These fibers along with the obtained microcellulose can represent a new use for the almond shells that are mainly used as firewood.
Bioreactors for brine denitrification produced during polluted groundwater desalination in fertigation areas of SE Spain: batch assays for substrate selection.
Increasing knowledge of nitrate removal using denitrifying bioreactors has illustrated the usefulness of this management practice for treating discharge water from agricultural land uses. The objective of this study was to assess the viability of almond shell, chopped carob, olive bone, and citrus woodchip as carbon media for denitrification of brine with high nitrate load (EC ≈ 20 dS m-1, NO3--N concentration ≈ 65-80 mg NO3--N L-1) in bioreactors. To the authors' knowledge, this is the first test of denitrifying brine using organic wastes as the carbon substrate, and the first use of these carbon media for that purpose. Nitrate removal efficiency and efficiency:cost ratio were considered. The results indicated that the best removal efficiency and cheapest cost were provided by citrus woodchip (3.02 ± 0.15 mg NO3--N m-3 d-1) at a cost of ≈ 6€ m-3, followed by almond shell (1.54 ± 0.20 mg NO3--N m-3 d-1) at a cost of ≈ 19€ m-3. Chopped carob and olive bone showed negligible nitrate removal in the brine; chopped carob generated acidic leachate with extremely high dissolved organic carbon, and olive bone resulted in a highly saline leachate. Of the four media tested, the results of this study indicated that citrus woodchip was the most suitable media for denitrification of the brine.
Removal of ochratoxin A from liquid media using novel low-cost biosorbents.
Ground shells of almonds (ALM), hazelnuts (HAZ), walnuts (WAL), and chestnuts (CHE), coconut fiber (COC), spent coffee grounds (COF), and clementine peel (CLE) were used to remove ochratoxin A (OTA) from both water and an ethanol/water mixture (14:86, v/v). Other very efficient adsorbents like wood biochar (BC) and hydrochar (HC) and a humic acid (HA) were also adopted as a comparison. In batch experiments, sorption of OTA from water followed the trend BC (100% removed) > HA > CLE > COC > HC > COF > ALM > HAZ > CHE > WAL (8% removed), whereas sorption of OTA from ethanol/water mixture (14:86, v/v) onto only the raw materials was COC (54% removed) > CLE > HAZ > ALM > COF > CHE > WAL (0.4% removed). The desorption of the toxin from all materials in water was rather low. Afterwards, sorption kinetics and isotherms of OTA onto CLE, COC, and COF were performed. The three materials adsorbed OTA in about 2 h according to a pseudo-second-order kinetic model, thus indicating the occurrence of a chemisorption mechanism. Equilibrium sorption data of OTA onto CLE followed preferentially the Freundlich model, whereas those on COC and COF fitted well both Freundlich and Langmuir isotherms (r > 0.996). The values of Freundlich sorption constants, KFads, for CLE, COC, and COF were 313, 202, and 98 L kg-1, respectively. OTA desorption from each of the three materials showed hysteretic effects. Overall findings of this work suggest that raw plant wastes could be effectively used as biosorbents to abate the level of OTA in liquid media.