Tunisian date (Phoenix dactylifera L.) by-products: Characterization and potential effects on sensory, textural and antioxidant properties of dairy desserts

Does hydration of 'Deglet Nour' date palm fruits improve their quality and help to reduce waste?

This work investigates the quality change of date palm fruits after hydration treatment which is commonly applied to enhance the hard textured 'Deglet Nour' fruits that are unacceptable for consumption. Date palm fruits were treated at 60-62 °C with saturated steam for 4 h in three different processing units (DPU). Mid Infrared Spectroscopy (MIR) giving a global spectral evaluation discriminates samples from the three DPUs and highlights date palm fruits of the first DPU regarding hydration treatment. Treatment led to a decrease of fruit firmness, skin lightness, and of sucrose and malic acid contents whereas citric acid and procyanidins contents and procyanidins 'degree of polymerization increased. Thermal treatment had no effect on glucose and fructose contents, on cell wall content and composition and on minor phenolic groups. Significant differences existed on dates from the three DPUs, discriminating dates presenting high firmness. Hydration treatment improve dates texture as expected while nutritional parameters were quite stable, confirming that is very promising and could be highly recommended to valorise fruit that are currently not commercialized. However, optimisation is needed for the very hard-type dates.

Approaches to Enhance Sugar Content in Foods: Is the Date Palm Fruit a Natural Alternative to Sweeteners?

The current levels of added sugars in processed foods impact dental health and contribute to a range of chronic non-communicable diseases, such as overweight, obesity, metabolic syndrome, type 2 diabetes, and cardiovascular diseases. This review presents sugars and sweeteners used in food processing, the current possibility to replace added sugars, and highlights the benefits of using dates as a new natural, nutritious and healthy alternative to synthetic and non-nutritive sweeteners. In the context of environmental sustainability, palm groves afford a propitious habitat for a diverse array of animal species and assume a pivotal social role by contributing to the provisioning of sustenance and livelihoods for local communities. The available literature shows the date as an alternative to added sugars due to its composition in macro and micronutrients, especially in bioactive components (fiber, polyphenols and minerals). Therefore, dates are presented as a health promoter and a preventative for certain diseases with the consequent added value. The use of damaged or unmarketable dates, due to its limited shelf life, can reduce losses and improve the sustainability of date palm cultivation. This review shows the potential use dates, date by-products and second quality dates as sugar substitutes in the production of sweet and healthier foods, in line with broader sustainability objectives and circular economy principles.

Survival of Salmonella enterica and Listeria monocytogenes in date palm paste and syrup at different storage temperatures

This study aimed to investigate the behavior of Salmonella enterica and Listeria monocytogenes in processed date paste and syrup at different temperatures. Commercial products were inoculated with approximately 6 log CFU/mL of S. enterica or L. monocytogenes and stored at 4, 10, and 24°C for 90 days. S. enterica was able to survive in date products until the end of storage at 4°C. At this temperature, numbers decreased by 2.1 log CFU/g in date paste and by 3.4 log CFU/g in date syrup; however, at 10°C, cells were reduced >4.2 log CFU/g and were undetectable by direct plating in date paste or by enrichment (complete elimination) in syrup. Further, at 24°C, complete elimination of S. enterica was achieved in date paste and syrup by 30 and 7 days, respectively. L. monocytogenes numbers decreased by 1.4, 4.4, and >4.6 log CFU/g in date paste stored at 4, 10, and 24°C for 90 days, respectively. In date syrup, numbers of L. monocytogenes decreased to undetectable levels by 50, 14, and 4 days at 4, 10, and 24°C, respectively, by direct plating and complete elimination was observed at 10 and 24°C by 50 and 30 days of storage, respectively. The initial pH values of date paste and syrup were 4.7 and 4.8, respectively, and remained stable until the end of storage except for L. monocytogenes-inoculated syrup. PRACTICAL APPLICATION: Salmonella enterica and Listeria monocytogenes can easily survive in date paste and syrup particularly at refrigerator temperature, which explains the necessity of preventing the contamination of date products with foodborne pathogens.

Current Technologies and Uses for Fruit and Vegetable Wastes in a Sustainable System: A Review

The fruit and vegetable industry produces millions of tons of residues, which can cause large economic losses. Fruit and vegetable wastes and by-products contain a large number of bioactive substances with functional ingredients that have antioxidant, antibacterial, and other properties. Current technologies can utilize fruit and vegetable waste and by-products as ingredients, food bioactive compounds, and biofuels. Traditional and commercial utilization in the food industry includes such technologies as microwave-assisted extraction (MAE), supercritical fluid extraction (SFE), ultrasonic-assisted extraction (UAE), and high hydrostatic pressure technique (HHP). Biorefinery methods for converting fruit and vegetable wastes into biofuels, such as anaerobic digestion (AD), fermentation, incineration, pyrolysis and gasification, and hydrothermal carbonization, are described. This study provides strategies for the processing of fruit and vegetable wastes using eco-friendly technologies and lays a foundation for the utilization of fruit and vegetable loss/waste and by-products in a sustainable system.

Strategies for the Valorization of Date Fruit and Its Co-Products: A New Ingredient in the Development of Value-Added Foods

Date palm trees (Phoenix dactylifera L.) are traditionally cultivated in South-West Asia and North Africa for date fruit consumption, although in recent years, its consumption has increased worldwide, and its cultivation has spread to other areas of America, sub-Saharan Africa, Oceania, and Southern Europe. During date fruit processing, several types of by-products are generated, such as low-quality dates or seeds, which along with date fruit, represent an excellent source of dietary fiber and bioactive compounds such as flavonoids, tannins, carotenoids, tocopherols, and tocotrienols. Therefore, this review provides information on the processing of dates fruit and the value-added by-products generated from them as well as their applications in different types of foods for the development of foods with an enhanced nutritional and functional profile. The incorporation of date fruit and their co-products in food formulations will help to cover the current consumer demands for foods made with ingredients of natural origin and with health properties beyond the merely nutritional.

Effects of white mulberry powder fortification on antioxidant activity, physicochemical, microbial and sensorial properties of yogurt produced from buffalo milk

The objective of this study was to investigate the effects of sun-dried white mulberry fruit powder (WMFP) at addition levels of 2%, 4%, and 6% for enhancing nutritional value and improving the quality of yogurt during refrigerated storage. Results showed that the highest (p < .05) antioxidant activity of 54.53 ± 0.15% was observed in 6% WMFP-added yogurt samples. Highest pH of 4.53 ± 0.08 was observed in control. Significantly highest (p < .05) acidity (1.12 ± 0.02%) was recorded in the yogurt with 6% WMFP-added yogurt samples on 28th day. Moreover, the addition of WMFP elevated the total soluble solids up to 20.05 ± 0.02 °Brix and water-holding capacity up to 55.06 ± 0.34% and lessened the syneresis value (22.92 ± 0.25) in 6% yogurt samples. 2% WMFP-added yogurt sample was given the highest sensory score in terms of overall acceptability by the panelists (8.00 ± 0.00). Thus, it was concluded that fruit powder of white mulberry can be used to improve physicochemical and sensory properties of fortified yogurt. WMFP addition to yogurt enhanced its antioxidant potential and physicochemical quality. The study introduces white mulberry-enriched yogurt and suggests the food industries to launch this product in the market.

Development of fortified probiotic dairy desserts with added date extract, whey protein, inulin, folic acid, vitamin D and calcium

This study aimed to develop fortified dairy desserts containing Lactobacillus casei and evaluate the physicochemical, sensory, and microbiological characteristics of the product during 28 days of storage. Seven dairy desserts were formulated by date extract (8%), whey protein (1.56%), inulin (4%(, folic acid (0.00066%), vitamin D (0.002%) and gluconate calcium (0.66%). The addition of date extract and inulin increased total solids while whey protein incorporation into dairy desserts led to the improvement of protein and phosphorous content. Furthermore, all fortified dairy desserts showed higher antioxidant activity and total phenolic content. Fortification of dairy desserts had no negative effect on the sensory acceptability and syneresis was not observed. In addition, the pH reduction and increased acidity did not adversely affect the count of L. casei, which remained above 8 log CFU g-1 during storage. Consequently, the fortified dairy dessert developed in this research is an innovative food product with good acceptability and high nutritional quality.

Bioactivity and Pharmacological Potential of Date Palm (Phoenix dactylifera L.) Against Pandemic COVID-19: a Comprehensive Review

A novel coronavirus disease (COVID-19) or severe acute respiratory syndrome-related coronavirus 2 (SARS-CoV-2), transmitted from person to person, has quickly emerged as the pandemic responsible for the current global health crisis. This infection has been declared a global pandemic, resulting in a concerning number of deaths as well as complications post-infection, primarily among vulnerable groups particularly older people and those with multiple comorbidities. In this article, we review the most recent research on the role of date palm (Phoenix dactylifera L.) fruits (DPFs) to prevent or treat COVID-19 infection. The mechanisms underlying this preventive or therapeutic effect are also discussed in terms of bioactivity potentials in date palm, e.g., antimicrobial, antioxidant, anticancer, anti-diabetic, anti-inflammatory, neuroprotective, and hemolytic potential, as well as prospect against COVID-19 disease and the potential product development. Therefore, it can be concluded that regular consumption of DPFs may be associated with a lower risk of some chronic diseases. Indeed, DPFs have been widely used in folk medicine since ancient times to treat a variety of health conditions, demonstrating the importance of DPFs as a nutraceutical and source of functional nourishment. This comprehensive review aims to summarize the majority of the research on DPFs in terms of nutrient content and biologically active components such as phenolic compounds, with an emphasis on their roles in improving overall health as well as the potential product development to ensure consumers’ satisfaction in a current pandemic situation. In conclusion, DPFs can be given to COVID-19 patients as a safe and effective add-on medication or supplement in addition to routine treatments.

Characterization of functional sweetened condensed milk formulated with flavoring and sugar substitute

In the present study, the effect of sugar replacement and enrichment with cinnamon extract (CE) on the physicochemical, functional, and organoleptic properties of sweetened condensed milk (SCM) and the production of flavored functional dairy dessert was investigated. The results demonstrated that by adding CE (0.5 and 1%) and fructose sugar (50 and 100% replacement) in the formulation containing maltodextrin, the physicochemical, functional, and organoleptic properties of SCM samples were improved. However, adding fructose and CE at the maximum concentration increased the acidity, particle size, redness (a), yellowness (b) and decreased the lightness (L), viscosity, and sensory scores of the SCM samples (p < .05). Scanning electron microscopy images demonstrated that as the fructose level increased, the number of cavities increased, while the size of the cavities decreased (p < .05). Microstructure analysis also showed that the application of CE increased the density of the structure in the SCM samples. However, the SCM samples formulated with maltodextrin, 0.5% CE, and 50% fructose substitution were identified as optimal samples. Evaluation of the functional properties of SCM formulated with 0.5% CE revealed that the total phenolic content (TPC) and DPPH radical scavenging activity were in the range of 139.21-143.24 mg GAE / g and 50.12%-52.01%, respectively.

Date Fruit and Seed in Nutricosmetics

Many recent studies in the field of cosmetics have focused on organically sourced substances. Products made from organic materials are safe, high quality, cruelty-free, and more effective than those made from synthetic materials. Many organic compounds are known to be physiologically active in humans and have an extended storage capacity and long-lasting environmental effects. Agro-industrial waste has recently increased substantially, and the disposal of date palm waste, often performed in primitive ways such as burning, is harmful to the environment. Fruit processing industries generate over 10% of the total date seed waste daily, which could be converted into useful food products. Date fruit and seed are rich in sugar, vitamins, fiber, minerals, and phenolic compounds with antioxidant and anti-inflammatory properties that significantly promote human and animal health. This waste is rich in bioactive compounds and essential oils used in many kinds of food, medicine, and cosmetics. Most active cosmetic ingredients come from natural sources such as fruit, fish, and dairy, and recent research shows that date extract and seed oil help to reduce melanin, eczema, acne, and dry patches, while increasing skin moisture and elasticity. This review details the bioactive compounds and nutraceutical properties of date fruit and seed, and their use as cosmetic ingredients.

The Role of Fruit by-Products as Bioactive Compounds for Intestinal Health

The fruit processing industry generates large amounts of wastes (pomace, seeds, peels) that causes negative environmental impact with considerable treatment expenses. Nevertheless, various studies demonstrated that these by-products are still rich in bioactive compounds, especially dietary fibres and phenolic compounds, thus leading to significant chemical, physical and biological properties. These characteristics make fruits by-products a good source for new supplements in food products having important effect on intestinal function. Thus, the aim of this review is to evaluate the different bioactive compounds isolated from fruit by-products and to analyse their application in various formulations for the food and nutraceutical industries. In consideration of the biological properties of these compounds, their role in the functioning and action on intestine and gut flora was discussed.

Therapeutic Potential of Selected Varieties of Phoenix Dactylifera L. Against Microbial Biofilm and Free Radical Damage to DNA

Phoenix dactylifera L. (Date palm) is the most widely consumed fruit around the world and is rich source of nutrients containing dietary fibers, minerals, vitamins, sugar, protein and antioxidants with potent bioactivities against various microbial pathogens. This study evaluated the therapeutic potential of 2 varieties of ethanolic extracts of Phoenix dactylifera i-e Ajwa and Khalas against bacterial biofilms. This study also investigated the protective effect of Ajwa and Khalas against hydroxyl radical damage to calf thymus DNA. Antioxidant potential through different antioxidant assays showed that Ajwa has higher antioxidant potential than Khalas. Both Ajwa and Khalas presented good antimicrobial activities against Bacillus subtilis and Pasteurella multocida. Biofilm inhibition assay showed that increasing concentration of Ajwa and Khalas exhibited higher percentage of bacterial biofilm inhibition. Microscopic examination revealed significant inhibition of microbial biofilm. Ajwa and Khalas protected the calf thymus DNA against damage caused by hydroxyl radicals produced by fenton reagent. Fourier Transform Infrared (FTIR) spectra confirmed the presence of O–H, C=C and C–O functional groups in tested extracts. The study concluded that tested varieties of Date palm have the potential to inhibit bacterial biofilms and can be used for therapeutic purposes against biofilm producing pathogens.

High-Value Compounds in Fruit, Vegetable and Cereal Byproducts: An Overview of Potential Sustainable Reuse and Exploitation

Food waste (FW) represents a global and ever-growing issue that is attracting more attention due to its environmental, ethical, social and economic implications. Although a valuable quantity of bioactive components is still present in the residuals, nowadays most FW is destined for animal feeding, landfill disposal, composting and incineration. Aiming to valorize and recycle food byproducts, the development of novel and sustainable strategies to reduce the annual food loss appears an urgent need. In particular, plant byproducts are a plentiful source of high-value compounds that may be exploited as natural antioxidants, preservatives and supplements in the food industry, pharmaceuticals and cosmetics. In this review, a comprehensive overview of the main bioactive compounds in fruit, vegetable and cereal byproducts is provided. Additionally, the natural and suitable application of tailored enzymatic treatments and fermentation to recover high-value compounds from plant byproducts is discussed. Based on these promising strategies, a future expansion of green biotechnologies to revalorize the high quantity of byproducts is highly encouraging to reduce the food waste/losses and promote benefits on human health.

Development of a Novel Whey Date Beverage Fermented with Kefir Grains Using Response Surface Methodology

The aim of this study was to develop a novel kefir beverage using date syrup, whey permeate, and whey. The levels of the kefir grain inoculum (2–5% w/v), fruit syrup (10–50% w/v), and whey permeate (0–5% w/v) on pH, total phenolic content, antioxidant activity, lactic acid bacteria and yeast counts, and overall acceptability were investigated using central composite design. The use of response surface methodology allowed us to obtain a formulation with acceptable organoleptic properties and high antioxidant activities. The obtained beverages had total phenolic content, % DPPH scavenging activity, and overall acceptability ranging from 24 to 74 mg GAE/mL, from 74.80 to 91.37 mg GAE/mL, and from 3.50 to 6 mg GAE/mL (based on a 1 to 9 preference scale), respectively. Date syrup of 36.76% (w/v), whey permeates of 2.99%, and kefir grains inoculum size of 2.08% were the optimized process conditions achieved.

Quality Characteristics and Functional and Antioxidant Capacities of Algae-Fortified Fish Burgers Prepared from Common Barbel (Barbus barbus)

INTRODUCTION

Algae have been used as natural ingredients to produce new canned fish burgers prepared from minced flesh of common barbel. In this research, the impact of the addition of Cystoseira compressa and Jania adhaerens at concentrations of 0.5, 1, and 1.5% w/v on the texture and sensory characteristics of fish burgers were investigated.

RESULTS

Compared to controls, fish burgers containing 1% algae had better texture and sensory properties (P < 0.05). Also, these burger formulations had higher water and oil holding capacities as well as swelling ability, due to the important polysaccharides and dietary fibers contents of algae. In addition, algae-supplemented burgers were characterized as having low L⁎, a⁎, and b⁎ values, which made the color appear to be paler. Thanks to their high richness in pigments (chlorophylls and carotenoids) and polysaccharides, algae considerably enhance the antioxidant activities of the new ready-to-eat fish burgers. So, Cystoseira compressa and Jania adhaerens could be used as nutritious additives to produce new fish-based products.

Food Byproducts as Sustainable Ingredients for Innovative and Healthy Dairy Foods

The valorization of food wastes and byproducts has become a major subject of research to improve the sustainability of the food chain. This narrative review provides an overview of the current trends in the use of food byproducts in the development of dairy foods. We revised the latest data on food loss generation, the group of byproducts most used as ingredients in dairy product development, and their function within the food matrix. We also address the challenges associated with the sensory properties of the new products including ingredients obtained from byproducts, and consumers' attitudes towards these sustainable novel dairy foods. Overall, 50 studies supported the tremendous potential of the application of food byproducts (mainly those from plant-origin) in dairy foods as ingredients. There are promising results for their utilization as food additives for technological purposes, and as sources of bioactive compounds to enhance the health-promoting properties of dairy products. However, food technologists, nutritionists and sensory scientists should work together to face the challenge of improving the palatability and consumer acceptance of these novel and sustainable dairy foods.

Characterization of the Major Odor-Active Compounds in Dry Jujube Cultivars by Application of Gas Chromatography-Olfactometry and Odor Activity Value

The volatile compounds of jujube ( Ziziphus jujube Mill.) puree obtained from three cultivars, 'Jinsixiaozao' (Y1), 'Youzao' (Y2), and 'Yuzao' (Y3), were analyzed by gas chromatography-olfactometry (GC-O), gas chromatography-mass spectrometry, gas chromatography-flame photometric detection, and a nitrogen phosphorus detector. The results showed that a total of 37, 37, and 35 odor-active compounds were identified by GC-O in samples of Y1, Y2, and Y3, respectively. In addition, the odor activity value (OAV) was used to determine the important compounds. The results demonstrated that hexanal (OAV of 39-85), ( E)-2-octenal (OAV of 32-70), β-damascenone (OAV of 14-49), ethyl hexanoate (OAV of 22-39), 3-mercaptohexyl acetate (OAV of 17-24), and 2,5-dimethylpyrazine (OAV of 17-22) were key odor-active compounds. It is of great significance to develop high-grade jujube food by determining key odor-active compounds. Furthermore, four volatiles (hexanal, 1-octen-3-ol, 3-mercapohexyl acetate, and benzaldehyde) reduced the overall threshold value by 2.36, 1.01, 1.34, and 1.19, respectively.

Variations in Hormones and Antioxidant Status in Relation to Flowering in Early, Mid, and Late Varieties of Date Palm (Phoenix dactylifera) of United Arab Emirates

The present study was carried out to assess the status of various hormones responsible for the flower induction of Nagal, Lulu, and Khalas date palm varieties in UAE. The nonenzymatic antioxidant compounds and the antioxidant enzymatic activities at preflowering, flowering, and postflowering stages of the date palm varieties were quantified. The ABA and zeatin concentrations were found to be significantly higher during the preflowering stage but gradually decreased during the flowering period and then increased after the flowering stage. Gibberellic acid (GA) concentrations were significantly higher in the early flowering varieties and higher levels of ABA may contribute to the delayed flowering in mid and late varieties. The results on hormone profiling displayed a significant variation between seasons (preflowering, flowering, and postflowering) and also between the three date palms (early, mid, and late flowering varieties). Ascorbic acid (AA) concentration was low at the preflowering stage in the early flowering Nagal (0.694 mg/g dw), which is similar with the late flowering Lulu variety (0.862 mg/g dw). However, Khalas variety showed significantly higher amount of AA content (7.494 mg/g dw) at the preflowering stage when compared to other varieties. In flowering stage, Nagal (0.814 mg/g dw) and Lulu (0.963 mg/g dw) were similar with respect to the production of AA, while the mid flowering variety showed significantly higher amount of AA (9.358 mg/g dw). The Khalas variety produced the highest tocopherol at 4.78 mg/g dw compared to Nagal and Lulu, at 1.997 and 1.908 mg/g dw, respectively, during the preflowering stage. In Nagal variety, the content of reduced glutathione (GSH) at the preflowering stage was 0.507 mg/g dw, which was not significantly different from the flowering and postflowering stages at 0.4 and 0.45 mg/g dw, respectively. The GSH was significantly higher in Khalas compared to Nagal and Lulu varieties, at 1.321 mg/g dw in the preflowering phase followed by 3.347 mg/g dw and 2.349 mg/g dw at the flowering and postflowering phases, respectively. Catalase activity increased with different stages of growth. The lowest catalase activity was observed at the preflowering stage in Khalas (0.116), with similar observations noted during flowering (0.110) and postflowering stage. This study provides an insight into the possible roles of endogenous hormones and antioxidants and in the activities of antioxidant enzymes in the regulation of flower development in date palm varieties.