Characterization of novel intermediate food products from Spanish date palm (Phoenix dactylifera L., cv. Confitera) co-products for industrial use

Evaluation of date palm tree (Phoenix dactylifera L.) residues and wastage as alternative to some conventional feed resources for ruminant in the Southern Tunisia

In order to assess nutritive potential of date and palm tree residues as feed resources for ruminants in Tunisian oasis, sampled biomasses from Deglet Nour and Allig varieties were evaluated for chemical composition, in vitro fermentation and metabolizable energy contents. Results for chemical composition of fruit wastes showed that these substrates are a potential source of sugar (an average of 84.3 g/100 g DM for Deglet Nour dates and 73.4 g/100 g DM for Allig ones), low in fiber (an average of crude cellulose of 3.20% DM for Deglet Nour dates and 2.60% DM for Allig ones) and provided with phenolic compounds (an average of 0.93 g/100 g DM for Deglet Nour dates and 1.01 g/100 g DM for those of Allig). Date fruit wastes presented a relatively high-energy content as evaluated in vitro (ME ~ 2300 kcal/Kg DM). The other tree wastes were low in CP and sugar but high in lignified cell wall, with low ME contents. It was concluded that date and palm tree residues and wastes are not used to enhance the roughage quality. Such alternative is to valorize available resources in difficult conditions when forages are rare and expensive. Except for retired fruits which could enhance rumen fermentation by a rapid supply of energy (sugar) especially when synchronized with supply of rapidly available Nitrogen. However, palms and pedicels are nutritionally poor and may be classified as roughages, close to straws or poor quality hays.

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.

Pathological Characterization and Management of Lasiodiplodia theobromae, a Hemibiotroph with an Interkingdom Host Range

Heart rot disease, caused by Lasiodiplodia theobromae, is destructive for date palms and other woody plants. The disease was reported in several oases in Egypt, and the pathogen was found in association with infected trees suffering dieback and rachis blight. Seven phylogenetically distinct fungal isolates were selected, and their pathogenicity was confirmed on date palms. The isolates exhibited variable degrees of virulence on inoculated leaves, which confirms the variation. We examined the antifungal effect of microbial bioagents and plant extracts on heart rot disease. The isolates of Trichoderma spp. gave moderate reduction of the pathogen's linear growth (40 to 60%), whereas their exudates were ultimately ineffective. Bacillus spp. isolates, except for B. megaterium, were more effective against spore germination, giving 80 to 90% reduction on average. Among the examined plant extracts, garlic sap gave 98.67% reduction of linear growth followed by artemisia (15.5%) and camphor (24.8%). The extraction methods greatly influenced the antifungal efficiency of each extract because exposure to organic solvents significantly decreased the efficiency of all extracts, whereas hot water extraction negatively affected garlic sap only. Successful bioagents and plant extracts were further assayed for the suppression of heart rot disease on date palms. Both T. album and T. harzianum gave comparable degrees of suppression as by commercial fungicides. In addition, treatment before or during pathogen inoculation was the most effective because it significantly enhanced the expression of defense-related enzymes. Our findings suggest biopesticides possess a dual role in disease suppression and defense boosters for date palms suffering heart rot disease.

A Sustainable Approach for the Valorization of Underutilized Date Fruits

Secondary varieties of date fruits are often discarded because they do not have commercial value. However, their phytochemicals are very similar to those of the primary ones and therefore, they can be valorized as a source of compounds of interest, mainly phenols and dietary fiber. Their chemical composition changes with ripening, so their characterization throughout this process is of great significance. Date fruit samples were harvested at Khalal, Rutab, and Tamer stages, and a mixture of fruits from ornamental date trees was also analyzed. Aqueous and ethanolic extracts were studied for their phenolic composition. In aqueous extracts, phenols decreased with ripening, while in the ethanolic ones having higher phenolic content. Chelidonic acid, a γ-pyrone, was the major compound found in all extracts, but in the ethanolic ones, flavonoids were also present in similar amounts. After purification by adsorption chromatography, all extracts were assayed for their antimicrobial activity. Those from the Tamer stage showed the highest activity, especially against Gram-positive bacteria. The fibrous residues after aqueous and ethanolic extractions were also characterized. Their chemical composition suggested that they can be considered as a good source of prebiotic arabinoxylans and antioxidant fiber, whose antiradical activity correlated with their phenolic content. Date fruits from secondary varieties are promising as a worthwhile starting point for obtaining new value-added products.

Quality Characteristics of Fresh Date Palm Fruits of "Medjoul" and "Confitera" cv. from the Southeast of Spain (Elche Palm Grove)

The quality characteristics (physical, techno-functional, and chemical) of date fruits (at the tamar stage) of two cultivars ("Confitera", autochthonous and unknown vs. "Medjoul", widely distributed and well-known), grown in the Southeast of Spain (Elche palm grove) were evaluated in order to reinforce decisions aimed at organizing the production of fresh dates from Elche by selecting the most profitable cultivar. Morphologically, Confitera dates were longer and with higher pulp yield than Medjoul dates (4.58 cm vs. 3.88 cm, and 84% vs. 78%, respectively) (p < 0.05). Nutritionally, both dates are a good source of carbohydrates (total sugars (43-48%) and dietary fiber (20-22%)), with small amounts of fat and proteins. The main free sugars in dates from both cultivars were glucose and fructose (reducing sugars). The most abundant mineral found in both date fruits were K, followed by Ca or Mg (depending on the cultivar; Ca in Medjoul and Mg in Confitera). Confitera dates showed a higher total antioxidant activity than Medjoul, corresponding with their higher (p < 0.05) content in polyphenolic compounds, mainly flavonoids (catechin and epicatechin predominantly). Confitera dates should be promoted in this region not only for their contribution to sustainable agricultural development and biodiversity, but also for their higher overall quality.

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 Extraction and Evaporation Methods on Physico-Chemical, Functional, and Nutritional Properties of Syrups from Barhi Dates (Phoenix dactylifera L.)

Date fruits (Phoenix dactylifera L.) are rich in sugar and also contain a substantial amount of phenolic compounds. Therefore, date fruits can be used to produce an alternative sweetener, having lower glycemic index than sucrose. This study investigated the effects of extraction and evaporation methods on various properties of the syrups prepared from Barhi dates. Extraction of date juice with the aid of pectinase or cellulase significantly enhanced the production yield, total phenolic content, and antioxidant activities determined by Ferric Reducing Antioxidant Power and Oxygen Radical Absorbance Capacity assays. Syrups prepared without enzyme application had about 6–7 times higher apparent viscosity than those prepared from the enzyme-assisted extracted juices. Vacuum evaporation produced syrups with significantly lighter color and inferior antioxidant properties than open heating. Properties of date syrups prepared with or without enzyme-assisted extraction followed by open heat evaporation were not different. They had a glucose-to-fructose ratio close to 1:1, received good sensory acceptability scores of above 6 on a 9-point hedonic scale, contained a safe level (<40 mg/kg) of 5-hydroxymethyl-2-furfuraldehyde, and exhibited similar glass transition and melting temperatures; while a greater inhibition on α-amylase activity was observed in syrups obtained from enzyme-assisted extraction. The in vivo glycemic measurement revealed that the syrup prepared with the aid of Pectinex and open heating was classified as low glycemic index (GI = 55) and medium glycemic load (GL = 11). Thus, enzyme-assisted extraction of date juice using Pectinex could be used to produce a healthy natural sweetener from low quality date fruits.

Effect of probiotic Lactiplantibacillus plantarum and chestnut flour (Castanea sativa mill) on microbiological and physicochemical characteristics of dry-cured sausages during storage

The effect of chestnut flour (Castanea sativa Mill) on L. plantarum viability and physicochemical characteristics in a dry-cured sausage (Longaniza de Pascua) during storage is discussed. Four batches were prepared: CL with 3% chestnut flour added; CPL with 3% chestnut flour and 8.5 log CFU/g L. plantarum added; PL with 8.5 log CFU/g L. plantarum added and L, the batch control. The sausages were stored at 4 °C and 20 °C, and vacuum packed for 43 d. L. plantarum viability was affected by storage time (P < 0.001). However, higher L. plantarum counts at the final of storage were reached due to chestnut flour addition (P < 0.001). At room storage, chestnut flour caused a higher increase in TBARS values (P = 0.022). Nevertheless, all lipid oxidation treatments were in the range of accepted values at the sensory detection level. In conclusion, Longaniza de Pascua can be kept at 4 °C or 20 °C for 43 d without causing any rancidity problems.

Physicochemical Properties and Intestinal Health Promoting Water-Insoluble Fiber Enriched Fraction Prepared from Blanched Vegetable Soybean Pod Hulls

Different methods can be used to change the fiber compositions of food, and they consequently affect the physicochemical properties and physiological activities. The present study compared the effects of a blanching treatment on the physicochemical properties of water-insoluble fiber enriched fraction (WIFF) from three varieties of vegetable soybean pod hulls (tea vegetable soybean pod hull, TVSPH; black vegetable soybean pod hull, BVSPH; 305 vegetable soybean pod hulls, 305VSPH) and evaluated their effects on intestinal health in hamsters. Blanching may increase the soluble dietary fiber (SDF) content of WIFF in the 305VSPH variety by solubilizing cell wall components and releasing water-soluble sugars. Thus, the WIFF in the 305VSPH variety after blanching may be composed of cellulose and pectic substances. The WIFF of the blanched 305VSPH (B-305VSPH) variety exhibited the highest physicochemical properties, such as a water-retention capacity (11.7 g/g), oil-holding capacity (9.34 g/g), swelling property (10.8 mL/g), solubility (12.2%), and cation-exchange capacity (221 meq/kg), of the three varieties examined. The supplementation of B-305VSPH WIFF in the diet resulted in significantly (p < 0.05) lower cecal and fecal ammonia; activities of fecal β-d-glucosidase, β-d-glucuronidase, mucinase, and urease; as well as higher cecal total short-chain fatty acids relative to other diets. In addition, microbial analysis suggested that fecal bifidobacteria growth was enhanced by the consumption of B-305VSPH WIFF. Therefore, B-305VSPH WIFF may be applicable as a potential functional ingredient in the food industry for the improvement of intestinal health.

Physicochemical and Sensory Characteristics of Spreadable Liver Pâtés with Annatto Extract (Bixa orellana L.) and Date Palm Co-Products (Phoenix dactylifera L.)

Two novel ingredients were incorporated into spreadable liver pâtés to study their effect on physicochemical and sensory characteristics and their possible use in the meat industry. Fresh date (Phoenix dactylifera, cv. Confitera) co-products, as a paste (0%, 2.5% and 7.5%), and annatto (Bixa orellana) extract (0 and 128 mg/kg), as a colourant, and their combinations were incorporated into liver pâtés to study their effect on the final quality. The six formulations were analysed for chemical composition, physicochemical characteristics (pH, a_w, colour, emulsion stability, and texture), and sensory properties. Pâtés tolerated suitable incorporation of date paste, providing emulsifying activity and being able to counteract to some extent the emulsion destabilisation caused by the annatto. All formulations showed an acceptable sensory quality, particularly pâtés with annatto and 7.5% date paste, which was softer, juicier, and presented redness values similar to the control as well as better emulsion stability. The combined use of these novel ingredients could be used as natural ingredients.

Metabolite profiling in 18 Saudi date palm fruit cultivars and their antioxidant potential via UPLC-qTOF-MS and multivariate data analyses

Date palm fruit (Phoenix dactylifera) is not only one of the most economically significant plants in the Middle East, but also valued for its nutritional impact, and for which development of analytical methods is ongoing to help distinguish its many cultivars.