Exploring the Untapped Potential of Pine Nut Skin By-Products: A Holistic Characterization and Recycling Approach
The increasing population, food demand, waste management concerns, and the search for sustainable alternatives to plastic polymers have led researchers to explore the potential of waste materials. This study focused on a waste of pine nut processing referred to in this paper as pine nut skin. For the first time, its nutritional profile, potential bioactive peptide, contaminants, and morphological structure were assessed. Pine nut skin was composed mainly of carbohydrates (56.2%) and fiber (27.5%). The fat (9.8%) was about 45%, 35%, and 20% saturated, monounsaturated, and polyunsaturated fatty acid, respectively, and Omega-9,-6, and -3 were detected. Notably, oleic acid, known for its health benefits, was found in significant quantities, resembling its presence in pine nut oil. The presence of bioactive compounds such as eicosapentaenoic acid (EPA) and phytosterols further adds to its nutritional value. Some essential elements were reported, whereas most of the contaminants such as heavy metals, polycyclic aromatic hydrocarbons, rare earth elements, and pesticides were below the limit of quantification. Furthermore, the in silico analysis showed the occurrence of potential precursor peptides of bioactive compounds, indicating health-promoting attributes. Lastly, the morphological structural characterization of the pine nut skin was followed by Fourier Transform Infrared and solid-state NMR spectroscopy to identify the major components, such as lignin, cellulose, and hemicellulose. The thermostability of the pine nut skin was monitored via thermogravimetric analysis, and the surface of the integument was analyzed via scanning electron microscopy and volumetric nitrogen adsorption. This information provides a more comprehensive view of the potential uses of pine nut skin as a filler material for biocomposite materials. A full characterization of the by-products of the food chain is essential for their more appropriate reuse. https://doi.org/10.3390/foods13071044
Effect of Pretreatment and Drying on the Nutritional and Functional Quality of Raisins Produced with Seedless Purple Grapes
Raisins, known for their delicious taste and high nutritional value, are among the most widely consumed dried fruits globally. The natural waxy layer on the surface of grapes impedes water migration, making pretreatment necessary before drying. This study evaluated the effects of various pretreatment methods on the nutritional and functional quality of seedless purple raisins. By using non-pretreated dry seedless purple raisins as a control, the impact of physical and chemical pretreatment methods on the nutritional and functional qualities of seedless purple raisins was assessed through the analysis of nutrient content, phenolic compounds, and antioxidant activity. Our results demonstrate that physical pretreatment significantly increases the levels of vitamin C, fructose, glucose, total acid, total phenolics, total flavonoids, total anthocyanins, and antioxidant activity compared to chemical pretreatment and the control group. The correlation analysis revealed that phenolic substances were closely linked to antioxidant capacity. Additionally, phenolic compounds, including resveratrol, ferulic acid, chlorogenic acid, ethyl coumarate, and cinnamic acid, were more abundant following physical pretreatment. The OPLS-DA model effectively differentiated the three groups of processed samples, showing that different pretreatments significantly affect the nutritional and functional quality of seedless purple raisins. These findings suggest that physical pretreatment offers considerable potential for improving the drying quality of seedless purple raisins. https://doi.org/10.3390/foods13081138
A Healthy Brazil Nut Beverage with Opuntia stricta var. dillenii Green Extract: Beverage Stability and Changes in Bioactives and Antioxidant Activity during Cold Storage
Plant-based beverages are one of the foods that currently arouse a lot of interest in the population due to their composition with compounds beneficial to health in addition to their being used as milk substitutes for people who suffer from food disorders. Also, their fortification with different nutrients or healthy ingredients with the aim of improving plant-based health potential is actually gaining importance in the food industry. For this reason, the aim of the present investigation was the preparation of a healthy Brazil nut beverage enriched with Opuntia stricta var. dillenii pulp green extracts (ODPs), in order to produce a healthy plant-based beverage with improved nutritional characteristics. The microstructural characterization of the Brazil nut beverage, its stability during cold storage for up to 24 days at 5 °C, the composition of bioactive compounds provided via ODP extract (betalains and phenolic compounds), and their antioxidant activity were evaluated in this study. Green ODP extracts (0.5 and 1 g/100 g beverage) were added to a standardized Brazil nut beverage (reduced fat beverage). The characterization of the bioactive composition (betalains and phenolic compounds) of the elaborated beverage was achieved via HPLC (UV-vis and MS-QT of detection), and the antioxidant activity measurements via ORAC were also carried out. Optical microscopy, particle size, and Z potential analysis was conducted to characterize the structure of the Brazil nut beverages as food emulsions in which ODP extract was added. Most of the bioactive compounds from the green ODP extract added to the beverages showed good retention and remained stable throughout the 24 days of storage at 7 °C, with encapsulation efficiencies ranging from 98.34% to 92.35% for betalains and from 93.67% and 81.20% for phenolic compounds. According to the results of this study, Brazil nut beverage seems to be a healthy and efficient food emulsion system to encapsulate ODP extract rich in betalains and phenolic compounds, with high antioxidant activity, making possible the development of a Brazil nut beverage with improved health potential. https://doi.org/10.3390/foods13081237
Rheological Characteristics of Wheat Dough Containing Powdered Hazelnuts or Walnuts Oil Cakes
This study assessed edible oil industry byproducts, oil cakes (OC) based on hazelnuts and walnuts (HOC, WOC), to replace wheat flour dough (WD) based on farinograph and extensograph parameters and rheological measurements. The research hypothesis of this work is that replacing part of wheat flour with ground nut oil cakes modifies the rheological characteristics of the dough. WF was replaced at the level of 5%, 10% and 15%. It was shown that use of OC in flour mixtures at various levels significantly influenced the rheological properties of the dough. The water absorption of wheat flour and oil cake mixtures was higher than that of the control sample, and the average value of this indicator was 53.4%. The control sample had the lowest dough development time (DDT), and the presence of HOC or WOC in the system resulted in a significant increase in this parameter (p < 0.05). The average DDT of WDHOC cakes was 4.7 min and was lower compared to WDWOC which was 5.9 min. The WDWOC10% and WDWOC15% samples were characterized by the highest dough stability value and the lowest degree of softening (p < 0.05). The presence of OC in the flour mixtures increased the values of the storage and loss moduli, which was reflected in the K′ and K″ values. The values of these parameters also increased as the level of OC addition increased. WDHOC doughs were characterized by higher values of the K′ and K″ parameters compared to WDWOC. The results of the creep and recovery test showed that the dough with the addition of nut OC was less susceptible to deformation compared to the control dough (p < 0.05). The resistance to deformation increased with the increasing share of HOC or WOC in the mixtures. The average value of viscoelastic compliance (J1) of this parameter for WDHOC dough was on average 1.8 × 10−4 Pa−1, and for WDWOC 2.0 × 10−4 Pa−1. Nut oil cakes are an interesting technological addition to the dough. Their use may have a positive impact on the characteristics of the finished product and expand their application possibilities in the food industry. This is because the dough with the addition of nut cakes was more stiff and less flexible and susceptible to deformation.
https://doi.org/10.3390/foods13010140
The Cardioprotective Properties of Selected Nuts: Their Functional Ingredients and Molecular Mechanisms
Nuts have been known as a nutritious food since ancient times and can be considered part of our original diet: they are one of the few foods that have been eaten in the same form for thousands of years. They consist of various dry fruits and seeds, with the most common species being almonds (Prunus dulcis), hazelnuts (Corylus avellana), cashews (cashew nuts, Anacardium occidentale), pistachios (Pistacia vera), walnuts (Italian nuts, Juglans regia), peanuts (Arachia hypogaca), Brazil nuts (Bartholletia excels), pecans (Corya illinoinensis), macadamia nuts (Macademia ternifolia) and pine nuts. Both in vitro and in vivo studies have found nuts to possess a range of bioactive compounds with cardioprotective properties, and hence, their consumption may play a role in preventing and treating cardiovascular diseases (CVDs). The present work reviews the current state of knowledge regarding the functional ingredients of various nuts (almonds, Brazil nuts, cashew nuts, hazelnuts, macadamia nuts, peanuts, pecan nuts, pine nuts, pistachios, and walnuts) and the molecular mechanisms of their cardioprotective action. The data indicate that almonds, walnuts and pistachios are the best nut sources of bioactive ingredients with cardioprotective properties.
https://doi.org/10.3390/foods13020242
Impact of Modified Atmosphere Packaging Conditions on Quality of Dates: Experimental Study and Predictive Analysis Using Artificial Neural Networks
Dates are highly perishable fruits, and maintaining their quality during storage is crucial. The current study aims to investigate the impact of storage conditions on the quality of dates (Khalas and Sukary cultivars) at the Tamer stage and predict their quality attributes during storage using artificial neural networks (ANN). The studied storage conditions were the modified atmosphere packing (MAP) gases (CO2, O2, and N), packaging materials, storage temperature, and storage time, and the evaluated quality attributes were moisture content, firmness, color parameters (L*, a*, b*, and ∆E), pH, water activity, total soluble solids, and microbial contamination. The findings demonstrated that the storage conditions significantly impacted (p < 0.05) the quality of the two stored date cultivars. The use of MAP with 20% CO2 + 80% N had a high potential to decrease the rate of color transformation and microbial growth of dates stored at 4 °C for both stored date cultivars. The developed ANN models efficiently predicted the quality changes of stored dates closely aligned with observed values under the different storage conditions, as evidenced by low Root Mean Square Error (RMSE) and Mean Absolute Percentage Error (MAPE) values. In addition, the reliability of the developed ANN models was further affirmed by the linear regression between predicted and measured values, which closely follow the 1:1 line, with R2 values ranging from 0.766 to 0.980, the ANN models demonstrate accurate estimating of fruit quality attributes. The study's findings contribute to food quality and supply chain management through the identification of optimal storage conditions and predicting the fruit quality during storage under different atmosphere conditions, thereby minimizing food waste and enhancing food safety.
https://doi.org/10.3390/foods12203811
Subcritical Water Extraction for Valorisation of Almond Skin from Almond Industrial Processing
Almond skin (AS) is an agro-industrial residue from almond processing that has a high potential for valorisation. In this study, subcritical water extraction (SWE) was applied at two temperatures (160 and 180 °C) to obtain phenolic-rich extracts (water-soluble fraction) and cellulose fibres (insoluble fraction) from AS. The extraction conditions affected the composition and properties of both valorised fractions. The dry extracts obtained at 180 °C were richer in phenolics (161 vs. 101 mg GAE. g-1 defatted almond skin (DAS)), with greater antioxidant potential (1.063 vs. 1.490 mg DAS.mg-1 DPPH) and showed greater antibacterial effect (lower MIC values) against L. innocua (34 vs. 90 mg·mL-1) and E. coli (48 vs. 90 mg·mL-1) than those obtained at 160 °C, despite the lower total solid yield (21 vs. 29%) obtained in the SWE process. The purification of cellulose from the SWE residues, using hydrogen peroxide (H2O2), revealed that AS is not a good source of cellulose material since the bleached fractions showed low yields (20-21%) and low cellulose purity (40-50%), even after four bleaching cycles (1 h) at pH 12 and 8% H2O2. Nevertheless, the application of a green, scalable, and toxic solvent-free SWE process was highly useful for obtaining AS bioactive extracts for different food, cosmetic, or pharmaceutical applications.
https://doi.org/10.3390/foods12203759
Occurrence of Mycotoxins in Dried Fruits Worldwide, with a Focus on Aflatoxins and Ochratoxin A: A Review.
Dried fruits are popular and nutritious snacks consumed worldwide due to their long shelf life and concentrated nutrient content. However, fruits can be contaminated with various toxigenic fungal species during different stages, including cultivation, harvesting, processing, drying, and storage. Consequently, these products may contain high levels of mycotoxins. This risk is particularly pronounced in developed countries due to the impact of climate change. Several factors contribute to mycotoxin production, including the type of fruit, geographical location, climate conditions, harvest treatments, and storage management practices. The main mycotoxins in dried fruits are aflatoxins (AFs) and ochratoxin A (OTA), which can induce human health problems and economic losses. Mycotoxin contamination can vary significantly depending on the geographic origin of dried fruits (vine fruits, figs, dates, apricots, prunes, and mulberries). The aim of this review was to fill the knowledge gap by consolidating data from various regions to understand the global picture and identify regions with higher contamination risks. By consolidating research from various origins and stages of the supply chain, the review intends to shed light on potential contamination events during pre-harvest, drying, storage, and trading, while also highlighting the effects of storage conditions and climate change on mycotoxin contamination.
https://doi.org/10.3390/toxins15090576
A Review on Extracts, Chemical Composition and Product Development of Walnut Diaphragma Juglandis Fructus.
Walnuts are one of the world's most important nut species and are popular for their high nutritional value, but the processing of walnuts produces numerous by-products. Among them, Diaphragma Juglandis Fructus has attracted the attention of researchers due to its complex chemical composition and diverse bioactivities. However, comprehensive reviews of extract activity and mechanistic studies, chemical composition functionality, and product types are scarce. Therefore, the aim of this review is to analyze the extracts, chemical composition, and product development of Diaphragma Juglandis Fructus. Conclusions: For extracts, the biological activities of aqueous and ethanol extracts have been studied more extensively than those of methanol extracts, but almost all of the studies have been based on crude extracts, with fewer explorations of their mechanisms. For chemical composition, the bioactivities of polyphenols and polysaccharides were more intensively studied, while other chemical constituents were at the stage of content determination. For product development, walnuts are mainly used in food and medicine, but the product range is limited. In the future, research on the bioactivity and related mechanisms of Diaphragma Juglandis Fructus can be further expanded to improve its value as a potential natural plant resource applied in multiple industries.
https://doi.org/10.3390/foods12183379
The Antioxidant Activities In Vitro and In Vivo and Extraction Conditions Optimization of Defatted Walnut Kernel Extract.
The objective of this study was to determine the antioxidant activities of defatted walnut kernel extract (DWE) and whole walnut kernel extract (WE) in vitro and in vivo. Three spectrophotometric methods, DPPH, ABTS, and FRAP, were used in in vitro experiments, and mice were used in in vivo experiments. In addition, response surface methodology (RSM) was used to optimize reflux-assisted ethanol extraction of DWE for maximum antioxidant activity and total phenolic content. The results of in vitro experiments showed that both extracts showed antioxidant activity; however, the antioxidant activity of DWE was higher than that of WE. Both extracts improved the mice's oxidative damage status in in vivo studies. An ethanol concentration of 58%, an extraction temperature of 48 °C, and an extraction time of 77 min were the ideal parameters for reflux-assisted ethanol extraction of DWE. The results may provide useful information for further applications of defatted walnut kernels and the development of functional foods.
https://doi.org/10.3390/foods12183417