Plum Kernels Research Articles

Novel organometallic catalyst for efficient valorization of lipids extracted from Prunus domestica kernel shell in sustainable fuel production

This study focuses on converting Plum Kernel Shell (PKS) waste biomass into biodiesel using a novel synthesized heterogeneous catalyst, contributing to the pursuit of renewable fuel from sustainable resources. Plum Kernel Shell (PKS) is waste biomass generated from plum fruit and available abundantly; utilizing it can help in many ways, such as overcoming environmental issues and promoting a circular economy. The precursor for the heterogeneous catalyst is derived from post-oil extraction waste biomass and further modified with metallic oxides (CuO and Mo) due to its acidic nature to enhance its efficacy for biodiesel production. Thorough characterization of the synthesized catalyst was conducted using analytical techniques such as XRD (X-ray diffraction), SEM (Scanning Electron Microscopy), EDS (Energy-Dispersive X-ray Spectroscopy), BET (Brunauer-Emmett-Teller), and XPS (X-ray Photoelectron Spectroscopy) to elucidate its nature and performance. The transesterification process was systematically optimized by varying parameters such as temperature, time, methanol-to-oil ratio, and catalyst loading. The optimized yield of 92.61 % of biodiesel resulted under ideal conditions, specifically at 65 °C, 150 min, 5 wt% catalyst loading, and an 18:1 M ratio. The biodiesel derived from PKS oil exhibited promising fuel properties encompassing cold flow properties, density, viscosity, cetane number, and flash point, validating its potential as a viable alternative fuel source. Furthermore, the synthesized novel catalyst demonstrated exceptional efficiency, retaining stability over five cycles without significant reduction in biodiesel yield. These findings underscore the viability of PKS biomass as a renewable and sustainable source for both catalyst synthesis and biodiesel production.

Harnessing plum (Prunus domestica L.) processing wastes for the fabrication of bio-composite edible films: An attempt towards a food circular bioeconomy

This study investigated the effects of different biopolymer matrices on the quality characteristics of edible films produced from plum kernel protein isolate (PKPI), arrowroot starch (ARS), and plum kernel oil (PKO). All eight film-forming matrices produced a self-supporting and peelable film. Among the formulations tested, a composite film containing 50% PKPI, 50% ARS, and 1% PKO (P50S50O) exhibited favourable features, including the highest glass transition temperature and tensile strength, which were 2.05 and 1.59-folds higher than PKPI film, respectively. The composite film (P50S50O) showed a reduced water vapour transmission rate (WVTR), permeance, and water vapour permeability (WVP) indicating a decreased affinity for moisture and an improved tortuosity of the vapour diffusion path. XRD analysis revealed a 55.75% increase in crystallinity, and SEM micrographs showed smoother and more homogeneously entrapped PKO in P50S50O films. Peak shifting in FT-IR spectra confirmed the development of additional cross-linking among various film-forming matrices, which improved the barrier, mechanical, and thermal properties of the composite films, paving the way for the prospective application of plum processing waste in the development of edible films and curbing the environmental pollution of plastics films.

Investigating the Effect of Supercritical Carbon Dioxide Treatment on the Rheological, Thermal, and Functional Properties of Plum (Prunus domestica L.) Kernel Protein Isolates

Plum kernels are a promising source of dietary proteins that are irretrievably lost during processing. The recovery of these underexploited proteins could be eminently vital for human nutrition. Plum kernel protein isolate (PKPI) was prepared and exposed to a targeted supercritical carbon dioxide (SC-CO2) treatment to diversify its effectiveness in industrial applications. The impacts of SC-CO2 treatment at different processing temperatures (30-70 °C) on dynamic rheology, microstructure, thermal, and techno-functional characteristics of PKPI were investigated. The results revealed that the dynamic viscoelastic characteristics of SC-CO2-treated PKPIs showed higher storage modulus, loss modulus, and lower tan δ value than native PKPI, indicating greater strength and elasticity of the gels. Microstructural analysis showed that the proteins experienced denaturation at elevated temperatures and resulted in the formation of soluble aggregates, which increased the heat requirement for thermal denaturation of SC-CO2-treated samples. SC-CO2-treated PKPIs demonstrated a decline of 20.74% and 30.5% in crystallite size and crystallinity. PKPIs treated at 60 °C showed the highest dispersibility, which was 1.15-fold higher than the native PKPI sample. SC-CO2 treatment offers a novel path to improve the techno-functional properties of PKPIs and extend its use in food and non-food applications.

Supercritical carbon dioxide treatment of plum (Prunus domestica L) kernel protein isolate: Impact on structural, thermal, physical, and functional properties

The effects of supercritical carbon dioxide (SC–CO2) treatment at varying processing temperatures (30–70 °C) on the physicochemical, structural, thermal, and functional properties of plum kernel protein isolate (PKPI) were investigated. The results revealed that SC-CO2 treatment at 60 °C reduced α-helical content (67.82%) and increased the β-sheet content (33.15%), which resulted in the greater stabilization of the oil-water emulsion (1.29-fold), enhanced foaming capacity (2.08-fold) and improved the solubility (1.23-fold). The fluorescence quenching in SC-CO2 treated PKPIs confirmed the conformational change in protein structure. A significant variation in denaturation temperatures (74.53–66.20 °C) and enthalpy values (133.16–93.98 J/g) of SC-CO2 treated PKPIs, indicates protein denaturation and the formation of new intermolecular bonds between proteins molecules. Furthermore, SC-CO2 treatment reduced the particle size and exerted a greater homogeneity, thereby offering new opportunities to extend its use in food applications.

Structural modification of plum (Prunus domestica L) kernel protein isolate by supercritical carbon-dioxide treatment: Functional properties and in-vitro protein digestibility

The effect of supercritical carbon dioxide (SC-CO2) treatment at different processing temperatures (30–70 °C) on the physico-functional properties, structural features, and in-vitro digestibility (IVPD) of plum kernel protein isolates (PKPI) was examined. The results revealed remarkable changes in the secondary structures of SC-CO2-treated PKPIs, including a decrease in α-helix proportion, a concomitant increase in β-sheet content, and a considerable variation in random coils and β-turn structures. The temperature rise increased the negative zeta potential to a maximum of 31.35 mV at 60 °C, exhibiting the colloidal stability of PKPI dispersions. SDS-PAGE analysis showed variations in the intensities of protein bands, indicating denaturation and aggregation at higher temperatures. These structural and molecular changes improved water-binding capacity (1.22-fold) and oil binding capacity (1.11-fold), wettability (1.12-fold), and the highest value in all the properties was recorded at 60 °C. Moreover, the highest IVPD value (21.58 %) and a distinguishable colour difference (∆E) of 8.11 was also obtained at 60 °C of the processing temperature. Therefore, SC-CO2 treatment-induced modification of PKPI contributed to the enhanced digestibility and techno-functional properties, which offered new prospects to extend its use in food applications.

Utilization of waste plum stones as a source of oil and catalyst for biodiesel production

Possibilities of using waste plum stones in biodiesel production were investigated. The plum kernels were used as a source to obtain oil by the Soxhlet extraction method, while the whole plum stones, the plum stone shells that remained after the crashing, and the plum kernel cake that remained after the oil extraction, were burned off to obtain ashes. The collected ashes were characterized by elemental composition, porosity, and base strength and tested for catalytic activity in transesterification of esterified plum kernel oil. Dominant elements were potassium, calcium, and magnesium at different contents in the three obtained ashes. The most active catalyst was the plum stone shell ash, so the effect of temperature (40, 50, and 60?C) on the reaction rate was investigated. The reaction rate constant increased with the reaction temperature with the activation energy value of 58.8 kJ mol-1. In addition, the plum stone shell ash can be reused as a catalyst after recalcination.

Synergistic effect of Fenton oxidation and adsorption process in treatment of azo printing dye: DSD optimization and reaction mechanism interpretation

ABSTRACT The main challenges to overcome within the Fenton process are the acidic pH as an optimal reaction condition, sludge formation in neutral pH medium and high toxicity of treated printing wastewater due to the generation of contaminating by-products. This research discusses the catalytic activity of homogeneous (FeSO4/H2O2) and heterogeneous (Fe2(MoO4)3/H2O2) Fenton processes in treatment of Yellow azo printing dye in synthetic aqueous solution and real printing effluent, with an integration of adsorption on functionalized biochar synthesized from wild plum kernels. The definitive screening design (DSD), was used to design the experiment. Independent variables were initial dye concentration (20–180 mg L−1), iron concentration (0.75–60 mg L−1), pH (2–10) and hydrogen peroxide concentration (1–11 mM). Higher decolourization efficiency of 79% was obtained within homogeneous Fenton treatment of printing wastewater, in comparison to heterogeneous Fenton treatment (54%), after a reaction time of 60 min. Same trend of mineralization degree was established: COD removal was 59% and 33% for homogeneous and heterogeneous Fenton process, respectively. The application of adsorption treatment has achieved significant advantages in terms of toxicity reduction (95%) and decolourization efficiency (90% of TOC removal and 22% of dye removal) of treated samples, even at neutral pH medium. Degradation mechanisms within Fenton and adsorption processes were proposed based on the qualitative gas chromatography/mass spectrometry analysis, physico-chemical properties of dye degradation products and functionalized biochar. Overall, the homogeneous Fenton/adsorption combined process can be potentially used as a treatment to remove azo dyes from contaminated water.

Removal of methylene blue using a novel generation photocatalyst based on nano-SnO2/wild plumb kernel shell biochar composite

A series of measurement results revealed that the nano-SnO2 (n-SnO2) nanoparticles were spread uniformly on the carbon surface inside the wild plum (Prunus domestica) kernel shell biochar (WPKSB) structure. The addition of hydrothermally synthesized n-SnO2 to WPKS improved both the adsorption capacity and the photocatalytic potential of WPKSB for methylene blue (MB) removal. When the initial MB content was 5 mg/L, the n-SnO2@WPKSB composite demonstrated high MB removal efficiency under UV light via a combined effect of adsorption and photocatalysis. The n-SnO2@WPKSB composite removed 99.5 (±0.4) % of the MB from the dye-polluted water sample in 105 minutes at pH of 7.0. Because of the synergistic effect of adsorption and photodegradation, the composite was more effective at treating the aqueous MB solution than WPKSB and n-SnO2 alone. Reusability tests were run to remove MB to assess the composite structure’s chemical stability and catalytic capacity. The n-SnO2@WPKSB composite was characterized using X-ray Diffraction, Fourier Transform infrared and Scanning Electron Microscopy. This research investigates how to make metal oxide/biochar nanocomposites with exceptional adsorption and photocatalysis properties for the oxidation and removal of MB.

Determination of Physico-Chemical and Functional Properties of Plum Seed Cakes for Estimation of Their Further Industrial Applications

The extraction of bioactive compounds from the waste material in the food industry is an important approach because, in that way, the plant raw material can be utilized before its landfill disposal or combustion. The interest of scientists is great for the development of innovative procedures for the further application of these materials. Plum kernels obtained after plum processing can be used for the isolation of oil enriched with unsaturated fatty acids and cakes remaining after oil isolation from plant material. This study aimed to consider the possibilities of the further utilization of cakes obtained after oil isolation from plum seeds using organic solvents in the Soxhlet extractor. The physical–chemical and functional properties of the obtained cakes were determined. The results indicated that the plum seed cakes are rich in proteins (36.95–61.90%) and crude fiber (6.36–9.85%). The HPLC analysis showed that the highest content of phenolic compounds had coumaric acid in the concentration range of 11.31–12.98 mg/100 g of dry weight. The amygdalin content (0.005–0.139 mg/g of dry weight) was in the allowed concentration range so that the cakes can be considered safe for human use. The antioxidant potential of the cakes (IC50 0.40–0.65 mg/mL) indicated that antioxidants are also present in this waste material so that the cakes can be used as a raw material for the development of sustainable products in the food, pharmaceutical, and cosmetic industries.

Case Report; Primary Aortoenteric Fistula Due to Plum Kernel

Introduction: Aortoenteric fistulas are defined as an abnormal connection between the aorta and any portion of the gastrointestinal tract. It can occur after aortic repair surgery or spontaneously (primary). The common clinical features of primary aortoenteric fistula are upper gastrointestinal bleeding, abdominal pain, and pulsatile abdominal mass. The reasons are inflammatory destruction of an aortic aneurysm, infection, tumors and ingestion of foreign bodies. 
 We represent a case of a primary aortoenteric fistula due to plum kernel which is rarely seen.
 Case Report: A 76-year-old man admitted to emergency department with abdominal pain. On computed tomography angiography, there was hypodense restricted lesion with widespread air image which was located around the abdominal aorta. It was determined that abdominal aorta is surrounded by organised hematoma. A plum kernel, was detected in the operating room, was the reason for the aortoenteric fistula. Graft was placed in the abdominal aorta. He died in the first day after surgery.
 Conclusions: Primary aortoenteric fistulas should be considered in differential diagnosis of abdominal pain, upper gastrointestinal bleeding and shock in patient with aortic aneurysm. Kernels of any fruit considered to be harmless just as plum kernel and should be noted that may cause aortoenteric fistula.

Evaluation of plant‐based oils for production of offset printing ink

AbstractThe oils and solvents are the main components of the printing ink, and the chemical composition of the ink could be harmful or toxic to human health and the environment. Therefore, there is an increasing demand to develop inks containing green, biobased, sustainable, and renewable raw materials instead of petrochemical substances. In this study, flaxseed oil (FO), pomegranate seed oil, plum kernel oil (PKO), and grape seed oil (GSO) were selected to produce offset printing inks. Pinus pinaster (P. pinaster) resin was also used in the formulation of inks to examine the effects of natural resin on ink together with vegetable oils. The phenolic content was analyzed for the resin and oils to figure out their potential antioxidant and bioactive characteristics. Optical and rheological tests were applied to evaluate the printability of the inks. L*a*b*, ΔE, density, and gloss tests were performed for optical evaluation. The viscosity, tack, and rub resistance tests were applied to perform rheological analysis. The biobased, environmental friendly, and self‐drying (cold set) offset printing inks were obtained using natural pine resin and three different plant‐based oils FO, PKO, and GSO. The printability analysis of the inks figured out the potential usage of plant‐based oils in the offset printing ink formulation.

Insights Into the Properties of Amygdalin Solvatomorphs: X-ray Structures, Intermolecular Interactions, and Transformations.

Amygdalin is an effective component of the traditional Chinese medicine bitter almond, peach kernel, and plum kernel. It has pharmacological effects, such as relieving cough and asthma. In a study of the crystallization process, we found a series of solvatomorphs of amygdalin (including hydrate). Interestingly, in the structures of these solvatomorphs, the same characteristic structural fragment is present, that is, amygdalin dihydrate. Multiple analytical techniques were used to characterize the solvatomorphs, such as X-ray diffraction and thermogravimetry–mass spectrometry. Void calculations of water and solvent were used to analyze the occupied volume in the unit cell of the corresponding solvatomorphs to explain the formation mechanism of the solvatomorphs from the perspective of space. To elucidate the formation mechanism of the solvatomorphs with this kind of characteristic structure from the perspective of energy, theoretical calculations based on density functional theory were applied, such as energy decomposition and molecular electrostatic potential surfaces. In addition, the transformation phenomenon between these solvatomorphs and amygdalin was identified, and the transformation pathways are described in detail.

Benchmarking Machine Learning Approaches to Evaluate the Cultivar Differentiation of Plum (Prunus domestica L.) Kernels

Plum fruit and kernels offer bioactive material for industrial production. The promising procedure for distinguishing plum kernel cultivars used in this study comprised two stages: image analysis to compute the texture parameters of plum kernels belonging to three cultivars ‘Emper’, ‘Kalipso’, and ‘Polinka’, and discriminant analysis using machine learning algorithms to classify plum kernel cultivars based on selected textures with the highest discriminative power. The discriminative models built separately for sets of textures selected from all color channels L, a, b, R, G, B, U, V, S, X, Y, Z, color space Lab and color channel b using the KStar (Lazy), PART (Rules), and LMT (Trees) classifiers provided the highest average accuracies reaching 98% in the case of the color space Lab and the KStar classifier. In this case, individual cultivars were discriminated with the accuracies of 97% for ‘Emper’ and ‘Kalipso’ to 99% for ‘Polinka’. The values of other performance metrics were also satisfactory, higher than 0.95. The ROC curves were quite smooth and steady with the most satisfactory curve for the ‘Kalipso’ kernels. The present study sheds light on an objective, non-destructive, and inexpensive procedure for cultivar discrimination of plum kernels.

Combined effect of microwave and hydrothermal treatment on anti-nutritional factors, antioxidant potential and bioactive compounds of plum (Prunus domesticaL.) kernels

The effect of microwave heating (450 W for 6 min), hydrothermal treatment (45 °C for 6, 9, 12 h) and their combination on antioxidant potential, anti-nutritional factors, and phenolic compounds of plum kernels were studied. Amygdalin and hydrocyanic acid content were reduced to undetectable amounts, while the phytic acid and tannins were reduced to 89.50 and 84.71%, respectively, when combined effects of microwave and hydrothermal (45 °C for 12 h) treatments were employed. Antioxidant activity and phenolic content were higher in microwave treated samples than hydrothermal and combined treatments. HPLC results revealed that combined treated samples have considerable amounts of phenolic compounds, particularly gallic acid, chlorogenic acid, (+)-catechin, syringic acid, rutin, 3,4-dihydroxy benzoic acid, tannic acid, and quercetin.

Synergistic effect of microwave heating and hydrothermal treatment on cyanogenic glycosides and bioactive compounds of plum (Prunus domesticaL.) kernels: An analytical approach

The effects of microwave heating (450 W for 6 min), hydrothermal treatment (6, 9, and 12 h at 45 °C) and their combination on compositional characteristics, cyanogenic glycosides, color, and bioactive compounds of plum kernels have been studied. The conditions examined caused a significant reduction of 37.81, 72.17, 84.41, 91.24 and 98.02% in cyanogenic glycosides of differently treated plum kernels. Total phenolic and total flavonoid compounds of plum kernels showed hydrothermal time-dependent duration decline. The larger shifts in FT-IR spectra near 1157 cm-1 provided valuable insights on the reduction of cyanogenic glycosides during combined treatments. The variation of color attributes (L*, a*, b*), during combined treatments indicates a more reddish tonality of plum kernel samples. The combined effect of hydrothermal (12 h at 45 °C) and microwave heating (450 W for 6 min) proved to be an effective tool for neutralizing the toxic effect of cyanogenic glycosides, opening up possibilities for its use in food industries.

Antioxidant potential, anti-nutritional factors, volatile compounds and phenolic composition of microwave heat-treated plum (Prunus domestica. L.) kernels: an analytical approach

PurposeThe study was aimed to explore the potential impact of microwave heating (450 W for 2, 4, 6 and 8 min) on antioxidant activity, anti-nutritional factors, volatile and phenolic compounds of the plum kernels.Design/methodology/approachPlum kernels are rich in proteins, lipids and bioactive compounds that are mostly underused and undervalued.FindingsThe results showed that microwave heating at 450 W for 6 min significantly (p < 0.05) increased the antioxidant activity, total phenolic and flavonoid content, while the longer treatment time (450 W for 8 min) adversely affected the phenolic compounds. Most importantly, the anti-nutritional factors like amygdalin, hydrocyanic acid, phytic acid and tannin content were reduced up to 87.1, 84.7, 20.9 and 46.2%, respectively at 450 W for 6 min treatment conditions, which was confirmed from the larger shifts observed in FT-IR spectra near 1,157 cm−1. Microwave heating at 450 W for 6 min also proved beneficial in improving the bioavailability of volatile and phenolic compounds including chlorogenic acid, gallic acid, syringic acid, (+)-catechin, caffeic acid, ß-carotene, trans-ferulic acid, rutin trihydrate, 3,4-dihydroxybenzoic acid, tannic acid and quercetin by liberating them from the plant matrix.Originality/valueThe results thus indicate that controlled microwave heating could be an effective approach for the reduction of anti-nutritional factors besides leading to an overall improvement in antioxidant potential and volatile and phenolic compounds. This novel technological approach can proliferate the use of plum kernels in different diversified food formulations.

Fabrication of a novel biopolymer‐based nanocomposite (nanoTiO2‐chitosan‐plum kernel shell) and adsorption of cationic dyes

AbstractBACKGROUNDThis study investigates the adsorption of methylene blue (MB) and malachite green (MG) onto a novel biosorbent. Rapid industrialization pollutes water resources, causing serious environmental problems. Physical and chemical treatments were performed for biosorbent modification.RESULTSIn the present work, nano (n)TiO2 was inserted into chitosan (Cts)‐epichlorohydrin (ECH)‐plum kernel shell (PKS) and the final product was characterized by various modern techniques such as Fourier transform infrared, X‐ray diffraction, scanning and transmission electron microscopy and thermogravimetric analysis. Under optimized conditions, the maximum adsorption capacities of MB and MG by Cht/PKS/nTiO2‐ECH (termed nTiO2‐Composite) determined by the Langmuir model were 86.96 and 108.70 mg g−1, respectively. Thermodynamic parameters such as ΔG°, ΔH°, ΔS° and Ea were calculated, confirming the interaction of dyes with nTiO2‐Composite as exothermic and spontaneous.CONCLUSIONSThis study shows that the newly synthesized nTiO2‐Composite has a very high performance in dye removal. © 2021 Society of Chemical Industry (SCI).

Analyzing the effects of hydrothermal treatment on antinutritional factor content of plum kernel grits by using response surface methodology

In this study, response surface methodology was used to optimize the conditions of hydrothermal treatment and their effect on amygdalin, hydrocyanic acid (HCN), tannin, and protein content of plum kernels grits. The conditions examined were soaking times ranging from 6 to 18 h and soaking temperatures from 25 to 45°C, which caused a significant decrease in amygdalin, HCN, tannin, and protein content of the plum kernels. The results showed that optimized hydrothermal conditions were soaking temperature of 45°C and soaking time of 9 h, with lower contents of amygdalin (2.89 mg / g), HCN (121.21 mg/kg), tannin (3.72 mg /100 g), and protein content (32.02 g/ 100 g). Under these optimized conditions, the reduction of amygdalin content, HCN content and tannin were 68.72 %, 79.59 %, and 72.64 %, respectively and the protein content was decreased by 10.92 % as compared to the initial amount. The results suggested that the optimized hydrothermal treatment could be an effective tool for neutralizing the toxic effect of anti-nutritional factors and improving the quality of the plum kernel grits.

Impact of plum processing on the quality and oxidative stability of cold-pressed kernel oil

Plum kernels of the “Čačanska rodna” variety, by-products from plum brandy production, were collected before and after fermentation and distillation, and used for cold-pressed oil production. Fatty acid and tocopherol contents were determined by capillary GC and HPLC, while the oxidation stability of the resulting cold-pressed oils was tested by the Rancimat method. The results showed that oleic fatty acid was dominant in the oil samples with a content of 56.6 to 61.8%, regardless of the plum kernels’ origin. The fermentation and distillation processes had a pronounced effect on the tocopherol content and oxidative stability of the resulting kernel oils. Tocopherol contents were 61.8 mg·100g-1, 87.4 mg·100g-1, 79.6 mg·100g-1 of oil, while the induction periods were 38.7, 44.4 and 33.6 hours for samples before fermentation, after fermentation and distillation, respectively. Based on the results, it could be concluded that the fermentation process increased the content of tocopherols in kernel oil whereas the high temperature during the distillation process adversely affected the tocopherol content and oxidative stability of the obtained kernel oil.

Unlocking the Secrets of Terminalia Kernels Using Near-Infrared Spectroscopy.

In recent years, the native food industry in Australia has increased in both value and volume due to the discovery of a wide range of phytochemicals (e.g., vitamin C, polyphenols) that have potential health benefits. Thus, plant organs and tissues of these native plants are used in a wide range of applications. In particular, the kernel of a native plum, the Kakadu plum (Terminalia ferdinandiana, Combretaceae) is considered to be rich in lipids and other phytochemical compounds. The aim of this study was to evaluate the use of NIR spectroscopy to analyze and characterize kernel samples and tissues of wild harvest fruit samples. The Fourier transform near-infrared reflectance spectra of cracked kernels, seeds cover tissues, and dry powder Kakadu plum kernels were acquired. Both principal component analysis and partial least squares discriminant analysis were used to analyze and interpret the spectral data. A correct classification rate of 93%, 86%, and 80% was achieved for the identification of kernel provenance using all tissues, seed coats, and the whole nuts, respectively. The results of this study reported for the first time the analysis of Kakadu plum kernels and their tissues using NIR spectroscopy.