The physicochemical properties, total phenolic, antioxidant activities, and phenolic profile of fermented olive cake

Improving the Rheological Properties of Dough Obtained by Partial Substitution of Wheat Flour with Freeze-Dried Olive Pomace

Mediterranean countries are known for their high-quality olives and the production and consumption of olive oil. Olive pomace (OP), the major by-product of olive oil extraction, is receiving attention for its potential as a functional compound in food products, reflecting its physiology- and health-promoting attributes. This study assessed the physico-chemical characteristics of OP obtained from two Sardinian olive cultivars, Bosana and Semidana, and the effect of OP incorporation on the baking performance of wheat dough. We assessed the rheological parameters, pasting profile, and fermentation of doughs obtained through the partial substitution of wheat flour with OP at 0 (control), 1, 2, 3, and 5%. OP inclusion resulted in significant differences in the studied parameters compared with control samples. Positive effects included a decrease in development time, improved dough stability and storage, and superior loss modulus and gas retention capacity. Negative effects comprised an increase in dough resistance and a decrease in dough development height, gas production, gas retention, pasting profile, stickiness, and elasticity. These differences in the OP dough were due to the interactions between polyphenols and fibre with water and the starch-gluten matrix. This study found improvements in dough characteristics following the substitution of wheat flour with low percentages of OP, especially Semidana at 1%. Although higher percentages of OP would be associated with greater nutritional and health benefits, they resulted in a degradation of the dough's attributes, producing a gluten-free-like matrix in the final product.

Olive oil and its derivatives for promoting performance, health, and struggling thermal stress effects on broilers

Olive oil (OL) production is the most significant agro-industrial business and has a high impact on the economy of numerous Mediterranean countries. However, OL extraction results in massive amounts of byproducts, including a solid residue (olive cake or olive pomace) and an aqueous stage (olive mill wastewater), which have serious environmental effects due to their hazardous nature and excessive organic content. Despite these byproducts causing environmental pollution, they can be applied for animal feeding. According to the literature, OL or its derivatives have been used to promote broiler performance, feed utilization, and health status in broilers as growth promoters or protein sources. Furthermore, using OL and its derivatives could improve heat resistance in stressed broilers via struggling thermal stress effects. In this framework, we highlighted the use of OL and its byproducts in broiler feeding to promote performance and health status. Additionally, the role of these byproducts and OL in combating thermal stress is investigated for sustainable strategy and promoting circular economy in broiler industry.

The Study of the Heterogeneity of the Qualities of Argan Oils and Pomaces from Different Cooperatives in the Essaouira Region (Morocco)

In this study, a comparison of the intra-regional variation in the quality of Argan oil and pomace collected from 12 cooperatives in the Essaouira region (Morocco) during the COVID-19 period was carried out. All studied Argan pomaces together with the extraction solvents showed a significant difference (p ≤ 0.05) in the total phenolic compounds, flavonoids, and tannins contents. The proteins, residual oils, total sugars, and total reducing sugars contents in the collected pomaces vary considerably among cooperatives of origin, with maximum averages of 50.45%; 30.05%; 3.82 milligrams of glucose equivalent per gram of dry matter; and 0.53 milligrams of glucose equivalent per gram of dry matter, respectively. Therefore, it is a very valuable ingredient for livestock feed and some cosmetic products that may contain it. The remaining Argan oil content in the pomace varied significantly among cooperatives, ranging from 8.74 to 30.05%. Pomace from traditional extraction recorded the highest content (30.05%), showing that the artisanal and modern extraction processes are not standardized. The measurements of acidity, peroxide value, specific extinction coefficient at 232 nm and 270 nm, and conjugated dienes were carried out in accordance with Moroccan Standard 08.5.090 in order to qualitatively classify all investigated Argan oils. Accordingly, the analyzed oils were categorized as "extra virgin Argan oil," "fine virgin Argan oil," "ordinary virgin Argan oil," and "lampante virgin Argan oil." Therefore, several factors can explain these variations in quality grades, both endogenous and exogenous. Overall, the variation observed in the obtained result allows us to deduce the most significant variables impacting the quality of Argan products and by-products.

Advances and Prospects of Phenolic Acids Production, Biorefinery and Analysis

Biotechnological production of phenolic acids is attracting increased interest due to their superior antioxidant activity, as well as other antimicrobial, dietary, and health benefits. As secondary metabolites, primarily found in plants and fungi, they are effective free radical scavengers due to the phenolic group available in their structure. Therefore, phenolic acids are widely utilised by pharmaceutical, food, cosmetic, and chemical industries. A demand for phenolic acids is mostly satisfied by utilising chemically synthesised compounds, with only a low quantity obtained from natural sources. As an alternative to chemical synthesis, environmentally friendly bio-based technologies are necessary for development in large-scale production. One of the most promising sustainable technologies is the utilisation of microbial cell factories for biosynthesis of phenolic acids. In this paper, we perform a systematic comparison of the best known natural sources of phenolic acids. The advances and prospects in the development of microbial cell factories for biosynthesis of these bioactive compounds are discussed in more detail. A special consideration is given to the modern production methods and analytics of phenolic acids.

Recovery of Natural Antioxidants from Agro-Industrial Side Streams through Advanced Extraction Techniques

Large amounts of agro-industrial waste are being generated each year, leading to pollution and economic loss. At the same time, these side streams are rich source of active compounds including antioxidants. Recovered compounds can be re-utilized as food additives, functional foods, nutra-/pharmaceuticals, cosmeceuticals, beauty products, and bio-packaging. Advanced extraction techniques are promising tools to recover target compounds such as antioxidants from agro-industrial side streams. Due to the disadvantages of classical extraction techniques (such as large amounts of solvents, increased time of extraction, large amounts of remaining waste after the extraction procedure, etc.), and advanced techniques emerged, in order to obtain more efficient and sustainable processes. In this review paper aspects regarding different modern extraction techniques related to recovery of antioxidant compounds from wastes generated in different industries and their applications are briefly discussed.

Influence of storage time and processing on chemical composition and in vitro ruminal fermentation of olive cake

Olive oil extraction generates olive cake (OC) that could be used in ruminant feeding. However, the chemical composition of OC is affected by multiple factors, being therefore highly variable. The objective of this study was to analyse the influence of storage time and further processing: crude, exhausted (subjected to a second oil extraction) and cyclone (obtained from a cyclone separator) on nutritive value of OC samples. Twelve samples (six crude and six exhausted) were obtained monthly from the same pond from 1 to 6 storage months, and nine samples (three crude, three exhausted and three cyclone) were obtained monthly from a different pond from 6 to 9 months storage. Chemical composition was analysed, and OC samples were fermented in vitro with sheep rumen fluid. Increasing storage time up to 6 months decreased sugars and total soluble polyphenols content but increased fibre content in OC. Dry matter effective degradability (DMED) decreased linearly (p < 0.001) by 35.9 and 45.5% as storage time augmented from 1 to 6 months for crude and exhausted OC, respectively. Crude OC had lower DMED values than exhausted OC (averaged values 0.255 and 0.294 g/g, respectively). Both potential production and rate of gas production were lower (p ≤ 0.018) in crude compared with exhausted OC, which was attributed to the high fat content of crude OC (≥86 g/kg dry matter). For samples stored longer than 6 months, cyclone had greater (p < 0.05) DMED than crude and exhausted OC (averaged values 0.207, 0.164 and 0.164 g/g, respectively). The results indicate that ruminal degradability of OC is reduced with advancing storage time, but only subtle changes were observed during the first two months. Cyclone showed greater degradability than crude and exhausted OC, but differences between crude and exhausted OC became negligible after five storage months.

Studies on the UV filtering and radical scavenging capacity of the bitter masking flavanone Eriodictyol

A computational analysis of UV filtering and radical scavenging capacity of a flavanone, Eriodictyol has been performed under DFT-B3LYP/6-31+ G (d, p). Eriodictyol is nontoxic and nonirritant bitter masker commonly used in the wine industry. It has been reported that the flavanones were widely acceptable for photoprotection due to its potential UV filtering and radical scavenging capacity. This study provides theoretical evidence that the eriodictyol has an absorbance in the UV-A and UV-B region of the electromagnetic spectrum and therefore can be used as a potential UV filter in sunscreen lotions and other cosmetic products. The major transitions in the UV-Visible spectrum of Eriodictyol are between HOMO and HOMO-1 with LUMO level and are well explained by NBO-NLMO tool in G09 software. In addition to this, Eriodictyol is a potent antioxidant than that of the most commonly studied Quercetin. The most active site in the compound is 3' position and is confirmed by NPA, NBO and pKa value analysis. The lowest energy conformer of Eriodictyol contains a Hydrogen bond between carbonyl oxygen (O2) and H30. This is confirmed by the highest value of interaction energy between lone pairs of O2 and σ* of O3- H30. Both the two lone pairs of O2 interacts with the σ* of O3-H30. This decreases the bond order of 5 OH and at the same time it restricts the hydrogen transfer from this position to form a radical. Similarly, the lone pair of O5 (3' position) interacts with H33 resulting in the low bond order value and consequently less favorable for radical formation. These results indicate that the BDE values follow the order 3' < 4' < 7 < 5. Thus the title compound can be used for photo protection due to its potential UV filtering and radical scavenging capacity.

Olive Mill Waste Extracts: Polyphenols Content, Antioxidant, and Antimicrobial Activities

Natural polyphenols extracts have been usually associated with great bioactive properties. In this work, we investigated in vitro antioxidant and antimicrobial potential of the phenolic olive mill wastewater extracts (OWWE) and the olive cake extracts (OCE). Using the Folin Ciocalteux method, OWWE contained higher total phenol content compared to OCE (8.90 ± 0.728 g/L versus 0.95 ± 0.017 mg/g). The phenolic compounds identification was carried out with a performance liquid chromatograph coupled to tandem mass spectrometry equipment (HPLC-ESI-MS). With this method, a list of polyphenols from OWWE and OCE was obtained. The antioxidant activity was measured in aqueous (DPPH) and emulsion (BCBT) systems. Using the DPPH assay, the results show that OWWE was more active than OCE and interestingly the extracts originating from mountainous areas were more active than those produced from plain areas (EC₅₀ = 12.1 ± 5.6 μg/mL; EC₅₀ = 157.7 ± 34.9 μg/mL, resp.). However, when the antioxidant activity was reversed in the BCBT, OCE produced from plain area was more potent than mountainous OCE. Testing by the gel diffusion assay, all the tested extracts have showed significant spectrum antibacterial activity against Staphylococcus aureus, whereas the biophenols extracts showed more limited activity against Escherichia coli and Streptococcus faecalis.