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

A new ingredient from date palm coproducts (pits) was obtained and tested as a preservative in burgers. Different concentrations of date pit (0%, 1.5%, 3%, and 6%) were added to beef burgers, and its effect on the safety and quality was evaluated during 10 days of storage. The incorporation of date pit was able to improve the shelf life and the cooking properties of the burgers. The date pit stabilized the color, lipid oxidation, and microbial growth of the burgers during the storage time due to the antioxidant activity and the phytochemical content of the date pits. For the consumer panel, the color and the off-odors were improved, and the addition of 1.5% and 3% date pit in cooked burgers obtained similar scores. Based on the obtained results, the new ingredient from date pit may have potential preservative properties for enhancing stability during shelf life and could improve the composition of bioactive compounds (fiber and phenolic content) of beef burgers.

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, aw, 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.

Phytochemicals in date co-products and their antioxidant activity.

The date agro-industry needs to find appropriate techniques to give value to their co-products. This study analyzes twelve intermediate food products (IFPs) from date co-products, Medjool and Confitera cv. at several ripening stages, blanched and unblanched, for their content in bioactive compounds (phenols, tannins, flavonoids, carotenoids and anthocyanins) and the antioxidant activity (AA). IFPs from the more unripe stages had the highest AA and phytochemicals content, mainly phenols, up to 1.4 g GAE/100 g, with high proportions of tannins. Flavonoids were found in high amounts, up to 874 mg RE/100 g. Among the AA are significant the antiradical efficiency (4.62 mM TE/100 g) and chelating activity (252 µM EDTA/100 g). Blanching was beneficial for Confitera IFPs. A positive correlation was found between phenols, tannins and flavonoids and the AA; and their content could be used as indicator of the AA. Date IFPs have potential use as an antioxidant functional ingredient.

Influence of fresh date palm co-products on the ripening of a paprika added dry-cured sausage model system.

Date palm co-products are a source of bioactive compounds that could be used as a new ingredient for the meat industry. An intermediate food product (IFP) from date palm co-products (5%) was incorporated into a paprika added dry-cured sausage (PADS) model system and was analysed for physicochemical parameters, lipid oxidation and sensory attributes during ripening. Addition of 5% IFP yielded a product with physicochemical properties similar to the traditional one. Instrumental colour differences were found, but were not detected visually by panellists, who also evaluated positively the sensory properties of the PADS with IFP. Therefore, the IFP from date palm co-products could be used as a natural ingredient in the formulation of PADS.

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

The nutritive, physicochemical and technological characteristics of several intermediate food products (IFPs) from Spanish Confitera fresh date co-products were investigated. Three IFPs were obtained, two from unblanched dates in different ripening stages (Khalal and Rutab), and a third one from blanched Khalal fruits. The IFPs were rich in dietary fibre (13-16%, dry matter), phenolics (0.56-4.26g GAE/100g dry matter) and sugars (55-82%, dry matter), with glucose and fructose as the predominant sugars. Malic acid was the major organic acid, and potassium was the main mineral. Blanching Khalal dates aided to prevent browning in the IFP, but also the thermal treatment modified the sugars profile. The results indicated that both maturity stages yield IFPs with potential in the food industry; and according to their sugar and phenolic content they could be suitable for the elaboration of new ingredients with different industrial applications. In addition, it would be recommendable blanching unripe fruits.

Date palm by-products as a new ingredient for the meat industry: application to pork liver pâté.

Date palm is an interesting source of bioactive compounds that could be used as ingredient in meat products; thus a campagne type pork liver pâté was elaborated using fresh date by-products (0, 5, 10 and 15%). Physicochemical properties, pigment and lipid oxidation, residual nitrite level, texture and sensory analysis during 4 days after the elaboration process were evaluated. Date paste mostly incorporated moisture, fibre and phenolic compounds. Physicochemical parameters, myoglobin content and heme iron stability were not severely affected. Addition of 10% of date was enough to avoid lipid oxidation through all storage times. Colour was the most affected parameter; however, in terms of overall acceptability, panellists preferred samples with added date.

Role of Oregano (Origanum vulgare) essential oil as a surface fungus inhibitor on fermented sausages: evaluation of its effect on microbial and physicochemical characteristics.

Oregano essential oil (OEO) was evaluated to determine its effect on the growth of natural contaminating molds on the surface of Spanish fermented sausage, the development of the internal microbial population of the sausage, and the physicochemical properties of the sausage. Results indicated a dramatic reduction in the contaminant molds. At the end of ripening, the main endogenous fungal species in control samples were Mucor racemosus (55%), Aspergillus fumigatus (20.6%), Cladosporium sphaerospermum (11.1%), Acremonium strictum (7.9%), and Aspergillus niger (4.7%). In samples treated with OEO, M. racemosus and A. fumigatus were the only species isolated; the treatment was more effective against A. fumigatus than against M. racemosus. The use of OEO to inhibit surface fungi did not affect the sausage drying process, pH, water activity, or color changes during ripening. These parameters change in a typical pattern for fermented dry-cured sausages during ripening. At the end of ripening, OEO-treated sausages had lower hardness and greater chewiness than the control but showed similar textural properties to sausages treated with potassium sorbate.

Lipolysis, proteolysis and sensory characteristics of a Spanish fermented dry-cured meat product (salchichón) with oregano essential oil used as surface mold inhibitor.

The superficial antifungal activity of oregano essential oil (OEO) in Spanish fermented dry-cured sausages ("salchichón"), and its effects on lipolysis, proteolysis and sensory characteristics were evaluated. The surface application of OEO reduced mold contamination on the surface, without significantly affecting the drying process. To evaluate the intensity of lipolysis during the ripening process, the profile and content of free fatty acids were determined. The addition of OEO led to a higher amount of unsaturated fatty acids, but lipolysis was not greatly affected. Sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE), which was used to qualitatively assess the proteolytic changes in the sarcoplasmic and myofibrillar proteins during the process, pointed to very similar patterns in all the sausages. OEO did not significantly affect the sensory properties, but increased hardness, resulting in a better texture. Therefore, a shorter ripening time may be necessary for sausages treated with OEO.