Effect of Date (Phoenix dactylifera L.) Pits on the Shelf Life of Beef Burgers

The utilisation of agricultural by-products in processed meat products: Effects on physicochemical, nutritional and sensory quality - Invited Review

Several plant-based materials are discarded by the food industry due to oversupply, lack of transport, and inappropriate storage. These materials contain valuable essential micronutrients such as minerals, vitamins and bioactive components (e.g., polyphenol, tocopherols, ascorbic acid, carotenoids) with antioxidant, antimicrobial, and anti-inflammatory effects, among others. In the context of making our agriculture-food based economy more circular and sustainable, and to develop foods with clean labels and less E-numbers, fruits, vegetables, yams, cereal distillers, oilseeds and other plant by-products could be utilised and upcycled back into new food formulations. Meat products are a particularly suitable matrix for this purpose, due to their susceptibility to lipid and protein oxidation and microbial spoilage (which shorten their shelf life). This review brings together the latest (2020-23) reformulation efforts, preservative methods and other innovative pathways, including studies on by-products as plant-based additives and bio-actives. It will cover the use of plant-based by-products as natural additives into production of processed meat products such as burgers, fermented meats and sausages, produced from ruminant and monogastric animals (except poultry). The extraction methods, inclusion levels, processing methods used and the quality of the resulting meat products will be reported, including preservative effects (microbial growth, oxidative stability and shelf life) and effects on instrumental, nutritional and sensory quality. Furthermore, it will also critically discuss the gaps identified, recommendation of the most promising ingredients for quality enhancement, and provide directions for future research.

Thermal and structural characteristics of date-pits as digested by Trichoderma reesei

The objective of this study was to develop functional date-pits by mold digestion for the potential use in food products. Whole date-pits (WDP) and defatted date-pits (DDP) were digested by mold Trichoderma reesei at 20 °C. T. reesei consumed date-pits as nutrients for their growth, and DDP showed higher growth of molds as compared to the WDP. The mold digested WDP and DDP samples showed an increased water solubility and hygroscopicity as compared to the samples prepared by autoclaved. This indicated that the mold digestion transformed date-pits to hydrophilic characteristics. Thermal analysis indicated a structural change at -3.2 °C for the untreated WDP and it was followed by a glass transition shift (i.e. onset: 138 °C and a specific heat change: 295 J/kg oC), and an endothermic peak at 196 °C with enthalpy of 68 J/g for the solids melting-decomposition. Similar characteristics were also observed for treated samples with the two glass transitions. The total specific heat changes for WDP, autoclaved-WDP, and digested-WDP were observed as 295, 367, and 328 J/kg oC, respectively. The total specific heat changes for DDP, autoclaved-DDP, and digested-DDP were observed as 778, 1329, and 1877 J/kg oC, respectively. This indicated that mold digestion transformed more amorphous fraction in the DDP. The energy absorption intensities of the Fourier Transform Infrared (FTIR) spectra for the selected functional groups decreased by the mold digestion.

Effects of Ajwa date seeds on the oxidative stability of butter

Butter is a widely used food product. However, owing to its rich fatty acid content (saturated and unsaturated fatty acids), it is prone to lipid oxidation, which may affect the quality of butter-containing products. Because of the possible toxic properties of synthetic antioxidants, recent research has focused on the use of natural antioxidants. This study aimed to evaluate the effects of Ajwa date seeds as natural antioxidants to retard lipid oxidation in butter. Date seeds as either a powder or extract were added to butter at concentrations of 0.5 % and 1 %; 100 % butter was used as the control. The samples were stored at 60 °C for 21 d. Radical scavenging activity, peroxide value, acid value, and thiobarbituric acid value (TBA) were analysed every 7 d. This study revealed a strong relationship between storage period and oxidative stability parameters. After 21 d, butter containing date seed powder exhibited higher radical scavenging activity than date seed extract. A reduction in peroxide, acid, and TBA values was also observed in butter samples containing date seed powder. In conclusion, date seed powder increased the oxidative stability of butter. Therefore, adding date seed powder to butter-rich food products can increase their shelf-life and stability.

Investigating the possibility of increasing the microbial and oxidative stability of silver carp burgers using hydrolyzed protein of watermelon seeds

In this study, watermelon seeds (Citrullus lanatus) protein hydrolyzed (WSPH) was produced using microbial enzymes Alcalase and Protamex. Then, the effect of different concentrations of WSPH (0, 1, 2, and 3%) on the quality of the silver carp (Hypophthalmichthys molitrix) burger during refrigerated storage (4 ± 1 °C) was investigated. According to the results, WSPH by alcalase had significantly higher degree of hydrolysis and antioxidant activity (p < 0.05) and it was used for burger tests. The results showed that, the addition of WSPH was able to reduce the microbial, chemical spoilage and sensory score during 16 days compared to the control, and with increasing the concentration of WSPH, better results were observed (p < 0.05). According to the chemical, microbial and sensory indicators, WSPH at 3% could increase the shelf life of fish burgers up to 8 days compared to the control, and this treatment was within the permissible quality limit until the end of the refrigerated storage.

Graphical abstract

Gelatin-sodium alginate packaging film with date pits extract: An eco-friendly packaging for extending raw minced beef shelf life

Gelatin-sodium alginate-based active packaging films were formulated by including date pits extracts (DPE), as bioactive compound, in raw minced beef meat packaging. The DPE effects at 0.37, 0.75 and 1.5% (w/w, DPE/ gelatin-sodium alginate) on physical, optical, antioxidant and antibacterial properties of established films were assessed. Findings showed that film lightness decreased with the incorporation of DPE. Physical, antioxidant and anti-food-borne pathogens capacities were enhanced by increasing DPE concentration in the films. For 2,2-Diphenyl-1-picrylhydrazyl (DPPH) and 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS), the films with 1.5% DPE had the greatest levels (94 and 88%, respectively). DPE films (1.5%) also exhibited the highest anti-Listeria moncytogenes activity, with an inhibition zone of 25 mm. Moreover, during 14 days at 4 °C, the bio-preservative impact of gelatin-sodium alginate film impregnated with DPE at three levels on microbial, chemical, and sensory characteristics of meat beef samples was evaluated. By the end of the storage, DPE at 1.5% enhanced the instrumental color, delayed chemical oxidation and improved sensory traits. By chemometric techniques (principal component analysis (PCA) and heat maps), all data allowed to obtain helpful information by segregating all the samples at each storage time. PCA and heat maps could connect oxidative chemical changes, instrumental color parameters, and microbiological properties to sensory attributes. These data offer an approach to well interpreting the sensory quality and how they are affected by chemical and microbiological changes in the studied meat samples. Our findings indicated the potential of the gelatin-sodium alginate film incorporated with DPE for enhancing meat safety and 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.

Physicochemical and Sensory Properties and Shelf Life of Block-Type Processed Cheeses Fortified with Date Seeds (Phoenix dactylifera L.) as a Functional Food

Processed cheese has rapidly been established as a commercial product in recent years. A new ingredient, a byproduct from date fruit seed (DFS), was obtained and tested as a fortified fiber from food industrial waste in block-type processed cheese. This is the first inclusive investigation to report such a test. Different concentrations of DFS (0%, 5%, 10%, 15%, and 20%) were added to block-type processed cheese as a partial substitution for butter. The current investigation was undertaken to estimate the impact of the partial substitution of butter by DFS and its effect on the product's quality in terms of its shelf life and physicochemical, microstructure, color, and sensory properties. Quality was assessed over a 150-day storage period. The results indicate that adding DFS to cheese increased its nutritional value due to the addition of fiber. Additionally, the texture profile of cheese was decreased in terms of hardness, adhesion, springiness, and cohesiveness. The overall structure of cheeses became less compact and had a more open cheese network, which increased with increasing DFS% and duration of storage. Moreover, DFS exhibited the darkest color with increasing ratios of supplementary DFS and duration of storage. Based on the results found in the present investigation, it was concluded that an acceptable quality of block-type processed cheese could be achieved using DFS fiber at 5% and 10% levels of fortification.

Applications of date pits in foods to enhance their functionality and quality: A review

Summary of the abstract

Chemical Characterization of Date Seeds (Phoenix dactylifera L.) Cultivated in Algeria for its Application as Functional Ingredients

Seven date seeds cultivars, Deglet Nour, Degla Baïdha, Fakht, Ghars, Hamraya, Tafezouin and Takermost were provided from Algerian Sahara. Some of these Algerian date seeds were studied for the first time (Fakht, Hamraya and Takermost). The biochemical characterization of these date seeds were studied, including fatty acids and minerals profiles. The results showed that date seeds are a good source of carbohydrates and crude cellulose, with averages of 66.63 and 13.20%, respectively. They are also a good source of proteins, with the cultivar Deglet Nour seeds as the richest one (9.27 ± 0.03%). The main fatty acid for all date seeds oils is oleic acid except for Deglet Nour in which lauric acid is the main one. However, the studied date seed oils could be classified as oleic-lauric oil. Potassium was the highest mineral in all date seeds cultivars, with values ranging from 2700 to 2900 mg/Kg, followed by sodium and iron. These results indicate that date seeds have good nutritional value with different compositions among cultivars. It could be concluded that date seeds could be considered as a good opportunity for their technological and industrial valorization.

The Effect of an Extract and Fractions of Date Pits on Some Plasma Constituents, Reproductive Hormones, and Testicular Histology in Male Mice

Pits of dates (Phoenix dactylifera L.) have numerous nutritional benefits that could have wide-ranging applications. This study aimed to examine the effects of administering three extracts from powdered date pits on some basic physiological parameters, plasma constituents, reproductive hormones, and testicular histology in CD1 male mice. Three groups received doses of 100 mg/kg/day of lyophilized extract, a nonpolar fraction, and a polar fraction of date pits by oral gavage for 28 consecutive days. For the control, one group was administered a 1 mL/kg concentration of distilled water. The three different extracts significantly increased the plasma testosterone level but showed no significant effect on estradiol or luteinizing hormone levels, except for estradiol reduction in the polar extract group. The measured physiological or biochemical parameters or testicular histology also demonstrated no significant differences between the control mice and those mice treated with the three extracts, except for reductions in plasma urea in all extracts and in total protein in the nonpolar extract. Therefore, date pit extracts may potentially be used as a safe and effective dietary supplement. However, further investigation is needed.

The Impact of Innovative Plant Sources (Cordia myxa L. Fruit (Assyrian Plum) and Phoenix dactylifera L. Biowaste (Date Pit)) on the Physicochemical, Microstructural, Nutritional, and Sensorial Properties of Gluten-Free Biscuits

The gluten-free products available on the markets are deficient in bioactive compounds and high in cost. The present study is designed to develop gluten-free biscuits with enhanced nutritional properties. The gluten-free biscuits are formulated with rice flour (RF) incorporated with Assyrian plum fruit flour (APF) and bio-waste date-pit flour (DPF) according to the following ratios; RF:DPF:APF (100:0:0)/T0, (90:5:5)/T1, (80:10:10)/T2, and (70:15:15)/T3. The results demonstrate that flour blends with different concentrations of APF and DPF incorporated in RF have high contents of protein, damaged starch, crude fiber, ash, phytochemicals, and antioxidants in contrast to 100% RF, which shows the lowest values for all these parameters. The pasting properties of the flour blends reveals that the values of peak, final, breakdown, and setback viscosities reduce from T1 to T3. Similarly, a differential scanning calorimeter reveals that the phase transition temperature of the flour blends decreases with the increasing amylose content. Moreover, the scanning electron microscopy of the biscuit samples shows a positive contribution of APF and DPF for the development of the desired compactness of the structure due to the leaching of amylose content from the starch. The total phenol content (TPC) and total flavonoid content (TFC) increase from 38.43 to 132.20 mg GAE/100 g DW and 18.67 to 87.27 mg CE/100 g DW, respectively. Similarly, the antioxidant activities of biscuits improved. The protein and fiber contents of the biscuits increased from 10.20 to 14.73% and 0.69 to 12.25%, respectively. The biscuits prepared from T3 resulted in a firmer texture with a reduced spread ratio. However, the formulation of T1 and T2 biscuit samples contributed to desirable physical and sensory properties. Therefore, the addition of DPF and APF to RF is a sustainable way to make gluten-free biscuits as they provide adequate amylose, damaged starch, and fiber content to overcome the essential role of gluten in the baked product with nutraceutical properties.

Date Components as Promising Plant-Based Materials to Be Incorporated into Baked Goods—A Review

Date (Phoenix dactylifera L. Arecaceae) fruits and their by-products are rich in nutrients. The health benefits of dates and their incorporation into value-added products have been widely studied. The date-processing industry faces a significant sustainability challenge as more than 10% (w/w) of the production is discarded as waste or by-products. Currently, food scientists are focusing on bakery product fortification with functional food ingredients due to the high demand for nutritious food with more convenience. Utilizing date components in value-added bakery products is a trending research area with increasing attention. Studies where the researchers tried to improve the quality of bakery goods by incorporating date components have shown positive results, with several drawbacks that need attention and further research. The objective of this review is to present a comprehensive overview of the utilization of date components in bakery products and to identify gaps in the current knowledge. This review will help focus further research in the area of valorization of date by-products and thereby contribute to the generation of novel functional bakery products that meet consumer expectations and industry standards, thus generating income for the relevant industry and considerable alleviation of the environmental burden this waste and by-products contribute to. Only a few studies have been focused on utilizing date by-products and their extracts for baked goods, while a research area still remaining under-explored is the effect of incorporation of date components on the shelf life of bakery products.

Date Seeds as a Natural Source of Dietary Fibers to Improve Texture and Sensory Properties of Wheat Bread

The aim of this work was to investigate the effect of date seed water-soluble polysaccharides (DSP) and hemicellulose (DSH) as dietary fiber sources in enhancing the wheat bread's quality. DSP and DSH were extracted from the three date seed varieties Deglet Nour, Ghars Souf, and Allig. The extraction yields ranged from 3.8% to 6.14% and from 13.29% to 18.8%, for DSP and DSH, respectively. DSP and DSH showed interesting functional properties and were incorporated at 0.5% and 0.75% (w/w) in wheat flour with low bread-making quality (FLBM). The results showed that the addition of 0.75% DSH significantly improved the alveograph profile of the dough, and in a more efficient way than that of DSP. Furthermore, bread evaluation revealed that the addition of DSH considerably improved the volume (by 24.22%) and the texture profile of bread (decrease of the hardness and chewiness by 41.54% and 33.81%, respectively), compared to control bread (prepared with FLBM). A sensory analysis showed that the better overall acceptability was found for bread supplemented with DSH. Results in this work demonstrate that hemicellulose fraction extracted from date seeds (DSH) and added with a level of 0.75% to FLBM represents the component that improved bread quality the best.

Effects of Boswellia Serrata and Whey Protein Powders on Physicochemical Properties of Pork Patties

Processed meat products are prone to oxidative damage and quality decline during storage; however, these problems can be mitigated by the proper formulation of meat productions. This study evaluated the effects of natural anti-oxidants found in Boswellia serrata (B), whey protein powder (W), and their combination on pork patties during storage, exploring changes in textural properties and lipid oxidation susceptibility. The 2% whey-added group exhibited a higher crude protein content than the untreated control group. The highest water-holding capacity and lowest cooking losses were observed in mixed-additive groups (WB₁ (2% W/0.5% B) and WB₂ (2% W/1.0% B), and the highest sensory scores for overall acceptability were obtained for WB₁. Adding B. serrata can neutralize the hardness caused by whey powder, thereby improving palatability. From 7 d (days 7), the extents of lipid oxidation, determined using 2-thiobarbituric acid-reactive substances (TBARS) analysis, for the WB₁ and WB₂ groups were significantly lower than that of the control group. The WB₁ and WB₂ groups exhibited substantially suppressed total bacterial colony and Escherichia coli counts relative to the control group. Our findings suggest that the additive combination of B. serrata and whey protein powders can suppress lipid oxidation, improve storage stability, and enhance textural properties in the production of functional pork patties.