Cereal foods fortified with by-products from the olive oil industry

Analysis of Olive Oil Mill Wastewater from Conventionally Farmed Olives: Chemical and Microbiological Safety and Polyphenolic Profile for Possible Use in Food Product Functionalization

This study aimed to perform an in-depth investigation of olive oil mill wastewater (OOMW). Two OOMW samples (OOMW-A and OOMW-B) from conventionally farmed olives were collected from two different olive oil mills in Palermo province (Italy). Multiresidual analysis indicated that both OOMW samples were unsuitable for food production due to pesticide residues. Specifically, OOMW-A contained 4 active compounds totaling 5.7 μg/L, while OOMW-B had 16 analytes with a total content of 65.8 μg/L. However, polyphenol analysis in the OOMW revealed 23 compounds with high concentrations of hydroxytyrosol, secoiridoid derivatives, phenolic acids, flavones, and total polyphenol content ranging from 377.5 μg/mL (for OOMW-B) to 391.8 μg/mL (for OOMW-A). The microbiological analysis of OOMW samples revealed only detectable viable bacteria (102 CFU/mL) of the lactic acid bacteria (LAB) group. Two distinct LAB strains, Lactiplantibacillus plantarum OMW1 and Leuconostoc mesenteroides OMW23, were identified. These strains demonstrated notable acidification capabilities and produced antibacterial compounds. In conclusion, despite the high polyphenolic content and microbiological suitability of OOMW, the presence of micro-contaminants hinders their use in food production. Thus, further studies are underway to investigate OOMW from organically farmed olives for bakery product functionalization, employing the two selected LAB strains resistant to olive polyphenols as leavening agents.

Enrichment of Breadsticks with Flavoured Oils: Chemical Composition, Antioxidant Activity and Technological and Sensory Properties

The present work compares the physical-chemical, organoleptic and antioxidant characteristics of breadsticks (Bs) prepared in the traditional way (BCs) with extra virgin olive oil (EVOO), and with mace (BMs), ginger (BGs) and turmeric (BTs) flavoured olive oil (FOO). Breadsticks' water activity (aw), pH, moisture content (U.R.), total phenol (TPC) and total flavonoid (TFC) content, colorimetric analysis and texture and sensory analysis were used to evaluate the impact of the new recipes on consumer acceptance. The radical scavenging activity was also assessed by using 1,1-diphenyl-2-picryl hydrazine (DPPH) and 2,2'-azinobis-3-ethylbenzothiazoline-6-sulfonate (ABTS). The use of FOO influenced breadsticks' colour with reference to the BG and BT enriched breadsticks, and some variability in free acidity values emerged from the comparison between EVOO and FOO. As expected, peroxide values increased in all enriched breadsticks. Moreover, all flavoured breadsticks were more resistant to lipid oxidation than BCs with an IP value of 92.44, 91.26 and 60.07 h, respectively, for BMs, BGs and BTs. The cooking process of the breadsticks at 180 °C for 25 min did not significantly impact the content of bioactive compounds. BMs showed the highest TPC and TFC with values of 996.32 and 534.41 mg/kg, respectively. Moreover, BMs showed the highest DPPH radical scavenging potential with a value of 393.91 µM TEAC/100 g extract, whereas BGs showed the highest ABTS radical scavenging activity (160.13 µM TEAC/100 g extract). Sensory quantitative descriptive analysis showed the most interesting parameters to be the intensity of toasting for BGs and the intensity of spiciness in BMs. Furthermore, BGs and BTs were found to have a slightly more pungent odour. From the texture assessment, the BC was the crumbliest breadstick, while greater crunchiness was found in the BG and BM samples.

Pasta Incorporating Olive Pomace: Impact on Nutritional Composition and Consumer Acceptance of a Prototype

The food industry is encouraged to develop new sustainable foodstuffs, and agri-food by-products can serve as valuable ingredients in these formulations. In this work, olive pomace (OP), a by-product of olive oil production, was incorporated as an ingredient in pasta. The changes in the nutritional composition and consumer acceptance were assessed, aiming to scale up the production. OP contains dietary fibre (55%), fat (9%), α-tocopherol (43 mg/kg), and oleic acid (76%) after moisture elimination. For that, the following two drying procedures were tested: 40 °C for 48 h (OP40) and 70 °C for 24 h (OP70). Both samples were sieved to remove the stone pieces. Drying at 70 °C (OP70) was the fastest method, revealed a better nutritional profile than OP40, and was the product selected for the incorporation into the pasta. The enriched pasta, containing 7.5% of OP70, was compared to a control. It showed an improved nutritional value with higher contents of fat, ash, fibre, vitamin E, oleic acid, phenolics, and flavonoids, a composition related to potential health benefits. Consumers appreciated the appearance, colour, shine, and aroma of the obtained pasta, making it a prototype with commercial viability. However, several improvements need to be implemented, namely, at the textural levels. Corrective actions, such as the optimisation of the amount of incorporated OP, the use of other ingredients for flavour masking, and textural adjustments, are advisable, thereby making this product more appealing and accepted by a larger number of consumers. This prototype can be a good approach for the circular economy, environmental sustainability, and food security.

Systematic screening for the biocatalytic hydration of fatty acids from different oily substrates by Elizabethkingia meningoseptica oleate hydratase through a Design-of-experiments approach

The edible plant oils production is associated with the release of different types of by-products. The latter represent cheap and available substrates to produce valuable compounds, such as flavours and fragrances, biologically active compounds and bio-based polymers. Elizabethkingia meningoseptica Oleate hydratases (Em_OhyA) can selectively catalyze the conversion of unsaturated fatty acids, specifically oleic acid, into hydroxy fatty acids, which find different industrial applications. In this study, Design-of-experiment (DoE) strategy was used to screen and identify conditions for reaching high yields in the reaction carried out by Escherichia coli whole-cell carrying the recombinant enzyme Em_OhyA using Waste Cooking Oils (WCO)-derived free fatty acids (FFA) as substrate. The identified reaction conditions for high oleic acid conversion were also tested on untreated triglycerides-containing substrates, such as pomace oil, sunflower oil, olive oil and oil mill wastewater (OMW), combining the triglyceride hydrolysis by the lipase from Candida rugosa and the E. coli whole-cell containing Em_OhyA for the production of hydroxy fatty acids. When WCO, sunflower oil and OMW were used as substrate, the one-pot bioconversion led to an increase of oleic acid conversion compared to the standard reaction. This work highlights the efficiency of the DoE approach to screen and identify conditions for an enzymatic reaction for the production of industrially-relevant products.

Metabolome classification of olive by-products from different oil presses providing insights into its potential health benefits and valorization as analyzed via multiplex MS-based techniques coupled to chemometrics

INTRODUCTION

The Olive (Olea europaea L.) is one of the most popular edible oil-producing fruits, consumed worldwide for its myriad nutritional and health benefits. Olive oil production generates huge quantities of by-products from the fruit, which are considered environmental hazards. Recently, more and more efforts have been made to valorize olive by-products as a source of low-cost, value-added food applications.

OBJECTIVE

The main objective of this study was to globally assess the metabolome of olive fruit by-products, including olive mill wastewater, olive pomace, and olive seeds from fruits from two areas, Siwa and Anshas, Egypt.

METHODS

Gas chromatography-mass spectrometry (GC-MS) and ultra-high-performance liquid chromatography with mass spectrometry (UPLC-MS) were used for profiling primary and secondary metabolites in olive by-products. Also, multivariate data analyses were used to assess variations between olive by-product samples.

RESULTS

A total of 103 primary metabolites and 105 secondary metabolites were identified by GC-MS and UPLC-MS, respectively. Fatty acids amounted to a major class in the olive by-products at 53-91%, with oleic acid dominating, especially in the pomace of Siwa. Mill wastewater was discriminated from other by-products by the presence of phenolics mainly tyrosol, hydroxyl tyrosol, and α-tocopherol as analyzed by UPLC-MS indicating their potential antioxidant activity. Pomace and seeds were rich in fatty acids/esters and hydroxy fatty acids and not readily distinguishable from each other.

CONCLUSION

The current work discusses the metabolome profile of olive waste products for valorization purposes. Pomace and seeds were enriched in fatty acids/esters, though not readily distinguishable from each other.

Exploitation of Black Olive (Olea europaea L. cv. Piantone di Mogliano) Pomace for the Production of High-Value Bread

In this study, the morpho-textural features, total phenolic content (TPC), and antioxidant capacity (AOC) of bread fortified with olive (Olea europaea L.) pomace were evaluated. Fresh olive pomace was subjected to microbiological and chemical (TPC, AOC, and fiber) analyses; then, the same olive pomace was analyzed during 1 to 6 months of storage at 4 °C or -20 °C. All olive pomace samples were used in 10%, 15%, or 20% amounts to produce type 0 soft wheat (Triticum aestivum) and whole wheat bread samples. The volatile organic compounds (VOCs) in the bread samples were also analyzed to assess the effect of the addition of the olive pomace on the flavor profile of the baked products. The TPC and AOC evaluation of olive pomace showed no differences among the analyzed samples (fresh, refrigerated, or frozen). Regarding the bread containing olive pomace, the specific volume was not affected by the amount or the storage methods of the added pomace. Bread samples produced with soft wheat flour showed the lowest hardness values relative to those produced with whole wheat flour, irrespective of the amount or storage method of the olive pomace. Regarding color, the crust and crumb of the bread samples containing 20% olive pomace were significantly darker. The bread samples containing 20% olive pomace had the highest TPC. The bread samples with fresh olive pomace were characterized by terpenoids, ketones, and aldehydes, whereas the bread samples containing refrigerated olive pomace were characterized by alcohols (mainly ethanol), acids, esters, and acetate. Finally, the bread samples with frozen olive pomace showed a volatile profile similar to that of bread produced with fresh olive pomace. Olive pomace was shown to be a suitable ingredient for producing bread with high nutritional value.

Regenerative Food Innovation: The Role of Agro-Food Chain By-Products and Plant Origin Food to Obtain High-Value-Added Foods

Food losses in the agri-food sector have been estimated as representing between 30 and 80% of overall yield. The agro-food sector has a responsibility to work towards achieving FAO sustainable goals and global initiatives on responding to many issues, including climate pressures from changes we are experiencing globally. Regenerative agriculture has been discussed for many years in terms of improving our land and water. What we now need is a focus on the ability to transform innovation within the food production and process systems to address the needs of society in the fundamental arenas of food, health and wellbeing in a sustainable world. Thus, regenerative food innovation presents an opportunity to evaluate by-products from the agriculture and food industries to utilise these waste streams to minimise the global effects of food waste. The mini-review article aims to illustrate advancements in the valorisation of foods from some of the most recent publications published by peer-reviewed journals during the last 4-5 years. The focus will be applied to plant-based valorised food products and how these can be utilised to improve food nutritional components, texture, sensory and consumer perception to develop the foods for the future.

Pasta Enriched with Carrot and Olive Leaf Flour Retains High Levels of Accessible Bioactives after In Vitro Digestion

The aim of this research was to evaluate the levels of antioxidants and polyphenols in pasta enriched with either carrot or olive leaf flours after simulating gastrointestinal digestion. Pasta samples were prepared with fixed amounts of carrot and olive leaf flours (15% and 6% of the total mixture, respectively). We measured the antioxidant capacity and polyphenol content at different stages of the pasta production process, starting from the initial flour to the cooked pasta, and tested samples of the liquid component and solid waste resulting from the digestion process. The antioxidant activity was measured by the FRAP method, while the polyphenol content was measured by the Folin-Ciocalteu method. Vitamin E contents were measured by HPLC. The pasta enriched with carrot (1.26 ± 0.05 mmol/100 g) and olive leaf (2.9 ± 0.07 mmol/100 g) exhibited higher antioxidant power compared to the unenriched pasta (0.8 ± 0.1 mmol/100 g). The polyphenol content followed a similar trend, with values of 131.23 ± 3.08 for olive flour-enriched pasta, 79.15 ± 1.11 for carrot flour-enriched pasta, and 67.5 ± 1.39 for the wheat-only pasta. The pasta samples maintained their antioxidant and polyphenol levels even after undergoing the simulated digestion process. Significantly, the liquid component of the pasta with olive leaf flours had the highest levels of antioxidants and polyphenols during all stages of the digestion process. According to the results of this study, pasta enriched with carrot and olive leaf flours shows promising potential for improving nutritional and functional properties by increasing antioxidant and polyphenol content. The samples were also evaluated by a sensory panel, which showed that fortification modified the perception of some organoleptic attributes without affecting the overall taste of the pasta.

Effect of Olive Pomace Extract Application and Packaging Material on the Preservation of Fresh-Cut Royal Gala Apples

The efficiency of natural olive pomace extracts for enhancing the quality of fresh-cut apples was compared with commercial ascorbic acid and two different packaging films (biodegradable polylactic acid (PLA) and oriented polypropylene (OPP)) were tested. The composition of atmosphere inside the packages, the physicochemical parameters (firmness, weight loss and color), the microbial load, total phenolic content and antioxidant activity of fresh-cut apples were evaluated throughout 12 days of storage at 4 °C. After 12 days of refrigerated storage, a significant decrease in O₂ was promoted in PLA films, and the weight loss of the whole packaging was higher in PLA films (5.4%) than in OPP films (0.2%). Natural olive pomace extracts reduced the load of mesophilic bacteria (3.4 ± 0.1 log CFU/g and 2.4 ± 0.1 log CFU/g for OPP and PLA films, respectively) and filamentous fungi (3.3 ± 0.1 log CFU/g and 2.44 ± 0.05 log CFU/g for OPP and PLA films, respectively) growth in fresh-cut apples after five days of storage at 4 °C, and no detection of coliforms was verified throughout the 12 days of storage. In general, the olive pomace extract preserved or improved the total phenolic index and antioxidant potential of the fruit, without significant changes in their firmness. Moreover, this extract seemed to be more effective when combined with the biodegradable PLA film packaging. This work can contribute to the availability of effective natural food additives, the sustainability of the olive oil industries and the reduction of environmental impact. It can also be useful in meeting the food industries requirements to develop new functional food products.

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

Summary of the abstract

Olive Mill Wastewater Fermented with Microbial Pools as a New Potential Functional Beverage

Olive mill wastewater (OMWW) represents a by-product but also a source of biologically active compounds, and their recycling is a relevant strategy to recover income and to reduce environmental impact. The objective of the present study was to obtain a new functional beverage with a health-promoting effect starting from OMWW. Fresh OMWW were pre-treated through filtration and/or microfiltration and subjected to fermentation using strains belonging to Lactiplantibacillus plantarum, Candida boidinii and Wickerhamomyces anomalus. During fermentation, phenolic content and hydroxytyrosol were monitored. Moreover, the biological assay of microfiltered fermented OMWW was detected versus tumor cell lines and as anti-inflammatory activity. The results showed that in microfiltered OMWW, fermentation was successfully conducted, with the lowest pH values reached after 21 days. In addition, in all fermented samples, an increase in phenol and organic acid contents was detected. Particularly, in samples fermented with L. plantarum and C. boidinii in single and combined cultures, the concentration of hydroxytyrosol reached values of 925.6, 902.5 and 903.5 mg/L, respectively. Moreover, biological assays highlighted that fermentation determines an increase in the antioxidant and anti-inflammatory activity of OMWW. Lastly, an increment in the active permeability on Caco-2 cell line was also revealed. In conclusion, results of the present study confirmed that the process applied here represents an effective strategy to achieve a new functional beverage.

Whole wheat bread enriched with silver fir (Abies alba Mill.) needles extract: technological and antioxidant properties

BACKGROUND

The interest of consumers and market and scientific research for added-value foods obtained with environmentally sustainable productive chains is increasing. Silver fir (Abies alba Mill.) needles (SFNs), often by-products of forest management and logging, represent an unexploited source of bioactive compounds.

RESULTS

For the first time, SFN aqueous extract obtained through controlled hydrodynamic cavitation was used to enrich whole wheat flour bread. The first trial found that 35% SFNs extract addition was the absolute threshold of taste perception. The second trial investigated dough rheological properties and bread technological and antioxidant properties in samples enriched with 35% and 100% SFNs extract compared with the control (0% SFNs extract). SFNs extract significantly increased bread antioxidant capacity in both 35% and 100% SFN fresh breads by ~42.5% and ~87% respectively and in 100% SFNs bread samples after 72 h of storage by ~76%. Enrichment of 35% showed higher alveograph dough extensibility (~11%) and different bread texture in terms of hardness, springiness, and chewiness. Enrichment with 100% SFNs extract significantly improved dough and bread technological quality: it increased alveograph dough extensibility L (~18%), swelling index G (~8%), and flour strength W (~14%) and showed the highest increase in bread specific volume (~0.200 L kg^-1 ).

CONCLUSIONS

SFNs aqueous extract produced with controlled hydrodynamic cavitation appeared a valuable technical material for the manufacturing of added-value and functional breads. © 2021 Society of Chemical Industry.

Olive Cake Powder as Functional Ingredient to Improve the Quality of Gluten-Free Breadsticks

The growing demand for high-quality gluten-free baked snacks has led researchers to test innovative ingredients. The aim of this work was to assess the feasibility of olive cake powder (OCP) to be used as a functional ingredient in gluten-free (GF) breadsticks. OCP was used by replacing 1, 2, and 3% of maize flour into GF breadstick production (BS1, BS2, BS3, respectively), and their influence on nutritional, bioactive, textural, and sensorial properties was assessed and compared with a control sample (BSC). BS1, BS2, and BS3 showed a higher lipid, moisture, and ash content. BS2 and BS3 had a total dietary fibre higher than 3 g 100 g⁻¹, achieving the nutritional requirement for it to be labelled as a “source of fibre”. The increasing replacement of olive cake in the formulation resulted in progressively higher total phenol content and antioxidant activity for fortified GF breadsticks. The L* and b* values decreased in all enriched GF breadsticks when compared with the control, while hardness was the lowest in BS3. The volatile profile highlighted a significant reduction in aldehydes, markers of lipid oxidation, and Maillard products (Strecker aldehydes, pyrazines, furans, ketones) in BS1, BS2, and BS3 when compared with BSC. The sensory profile showed a strong influence of OCP addition on GF breadsticks for almost all the parameters considered, with a higher overall pleasantness score for BS2 and BS3.

Byproducts from the Vegetable Oil Industry: The Challenges of Safety and Sustainability

Food loss and food waste are a global challenge as about one third of all food produced around the globe is lost or wasted at some point in the food supply chain, from the farm to the fork. Vegetable oils generate a considerable amount of waste and byproducts, and such byproducts represent valuable opportunities for the food industry. Given the obvious benefits of using byproducts, special attention should be paid to the safety issues, especially when it comes to reintroducing them into the food chain. In this study, the quality and safety of several vegetable oil industry byproducts were evaluated in order to further consider them as potential ingredients in functional foods. Microbiological tests, mycotoxin assessments, and a heavy metal analysis were performed. The microbiological analysis showed reduced contamination with spoilage microorganisms, and a lack of contamination with pathogenic bacteria. All of the samples noted levels of deoxynivalenol, and, with a few exceptions, the heavy metal levels were below the maximum allowed limits. This study also notes the lack of regulation for this category of products. This not only puts the possibility of capitalizing on many food byproducts at risk, but also their widespread use as ingredients for the production of new functional products and their safe consumption.

Nutritional Improvement of Gluten-Free Breadsticks by Olive Cake Addition and Sourdough Fermentation: How Texture, Sensory, and Aromatic Profile Were Affected?

There is a growing need for gluten-free bakery products with an improved nutritional profile. Currently, gluten-free baked goods deliver low protein, fiber, and mineral content and elevated predicted glycaemic index (pGI). Olive cake (OC), a by-product from virgin olive oil extraction, is an excellent natural source of unsaturated fatty acids, dietary fiber and bioactive molecules, including polyphenols and tocopherols. In this framework, this study aimed at using two selected lactic acid bacteria and a yeast for increasing the antioxidant features and the phenol profile of the gluten-free breadsticks fortified with OC with the perspective of producing a functional food. Control (CTR) samples were prepared and compared with fermented ones (fCTR). Samples were added with either non-fermented OC (nfOC) or fermented for 12 and 20 h (fOC-12 and fOC-20). Our results showed that the predicted glycemic index (pGI) was influenced by both OC addition and sourdough fermentation. In fact, the lowest value of pGI was found in fOC-12, and hydrolysis index and pGI values of samples with OC (fOC-12 and nfOC) were statistically lower than fCTR. Both OC addition and fermentation improved the total phenol content and antioxidant activity of breadsticks. The most pronounced increase in hardness values was observed in the samples subjected to sourdough fermentation as evidenced both from texture profile analysis and sensory evaluation. Moreover, in most cases, the concentration of the detected volatile compounds was reduced by fermentation. Our work highlights the potential of OC to be upcycled in combination with fermentation to produce gluten-free breadsticks with improved nutritional profile, although additional trials are required to enhance textural and sensory profile.

State of knowledge on chemical, biological and nutritional properties of olive mill wastewater

The Mediterranean olive oil industries are producing annually a massive quantity of olive mill wastewater (OMWW). Unfortunately, the OMWW is released arbitrarily in the nature without any pretreatment. Thus, it exhibits a high toxicity against the whole natural ecosystem including, microorganisms, plants and animals. In order to eliminate or reduce its pollution, OMWW must be properly treated prior to its release in the nature. In this regard, different treatment methods have been developed by researchers, but some of them were costly and others were inappropriate. Thus, more efforts should be made to save the nature from this pollutant. In the light of that, the current work summaries the state of knowledge regarding the OMWW from a chemical, biological, nutraceutical point of view, and the treatment methods that were used to eliminate its risk of pollution.

Olive Pomace and Pâté Olive Cake as Suitable Ingredients for Food and Feed

Olive oil extraction generates several by-products that represent an environmental issue, mainly for Mediterranean countries where olive oil is mostly produced. These by-products represent an ecological issue for their phenolic components, such as oleuropein, hydroxytyrosol, and tyrosol. However, olive oil by-products can be treated and properly exploited in different fields for their health-promoting properties, and they represent great potential for the food and beverage, cosmetic, and pharmaceutical industries. Furthermore, recovery and treatment processes can contribute to efficient waste management, which can enhance the sustainability of the olive oil industry, and in turn, lead to relevant economic benefits. The solid waste, i.e., olive pomace, could be considered to be a suitable matrix or primary resource of molecules with high added value due to their high phenolic content. Olive pomace, at different moisture contents, is the main by-product obtained from two- or three-phase extraction systems. A commonly used centrifugal extraction system, i.e., a multiphase decanter (DMF), does not require the addition of water and can generate a new by-product called pâté or olive pomace cake, consisting of moist pulp that is rich in phenols, in particular, secoiridoids, without any trace of kernel. Although several reviews have been published on olive wastes, only a few reviews have specifically focused on the solid by-products. Therefore, the aim of the present review is to provide a comprehensive overview on the current valorization of the main solid olive oil by-products, in particular, olive pomace or pâté olive cake, highlighting their use in different fields, including human nutrition.

By-Products Revalorization with Non-Thermal Treatments to Enhance Phytochemical Compounds of Fruit and Vegetables Derived Products: A Review

The aim of this review is to provide comprehensive information about non-thermal technologies applied in fruit and vegetables (F&V) by-products to enhance their phytochemicals and to obtain pectin. Moreover, the potential use of such compounds for food supplementation will also be of particular interest as a relevant and sustainable strategy to increase functional properties. The thermal instability of bioactive compounds, which induces a reduction of the content, has led to research and development during recent decades of non-thermal innovative technologies to preserve such nutraceuticals. Therefore, ultrasounds, light stresses, enzyme assisted treatment, fermentation, electro-technologies and high pressure, among others, have been developed and improved. Scientific evidence of F&V by-products application in food, pharmacologic and cosmetic products, and packaging materials were also found. Among food applications, it could be mentioned as enriched minimally processed fruits, beverages and purees fortification, healthier and "clean label" bakery and confectionary products, intelligent food packaging, and edible coatings. Future investigations should be focused on the optimization of 'green' non-thermal and sustainable-technologies on the F&V by-products' key compounds for the full-utilization of raw material in the food industry.

Applications of bioactive compounds extracted from olive industry wastes: A review

The wastes generated during the olive oil extraction process, even if presenting a negative impact for the environment, contain several bioactive compounds that have considerable health benefits. After suitable extraction and purification, these compounds can be used as food antioxidants or as active ingredients in nutraceutical and cosmetic products due to their interesting technological and pharmaceutical properties. The aim of this review, after presenting general applications of the different types of wastes generated from this industry, is to focus on the olive pomace produced by the two-phase system and to explore the challenging applications of the main individual compounds present in this waste. Hydroxytyrosol, tyrosol, oleuropein, oleuropein aglycone, and verbascoside are the most abundant bioactive compounds present in olive pomace. Besides their antioxidant activity, these compounds also demonstrated other biological properties such as antimicrobial, anticancer, or anti-inflammatory, thus being used in formulations to produce pharmaceutical and cosmetic products or in the fortification of food. Nevertheless, it is mandatory to involve both industries and researchers to create strategies to valorize these byproducts while maintaining environmental sustainability.

Phenolic Compounds from Irradiated Olive Wastes: Optimization of the Heat-Assisted Extraction Using Response Surface Methodology

Olive pomace, an environmentally detrimental residue generated during olive oil extraction, contains bioactive compounds in demand by the food industry. To valorize this waste product a suitable yield for the extraction process is required. Heat-assisted extraction of bioactive compounds from olive pomace was optimized by a circumscribed central composite design and response surface methodology. Our previous studies indicated that irradiation could improve 2.4-fold the extractability of the main phenolic compounds from olive pomace. The effect of extraction time, temperature and solvent concentration on the yield of polyphenols from irradiated olive pomace at 5 kGy was tested. Hydroxytyrosol-1-β-glucoside, hydroxytyrosol, tyrosol and caffeic acid were quantified by High Performance Liquid Chromatography to calculate the total polyphenol content. The optimal general conditions by RSM modeling were extraction time of 120 min, temperature of 85 °C, and 76% of ethanol in water. Using these selected conditions, 19.04 ± 1.50 mg/g dry weight, 148.88 ± 8.73 mg/g extract of total polyphenols were obtained, representing a yield of 13.7%, which was consistent with the value predicted by the model. This work demonstrated the potential of residues from the olive oil industry as a suitable alternative to obtain compounds that could be used as ingredients for the food industry.

Olive Mill Wastewater as Renewable Raw Materials to Generate High Added-Value Ingredients for Agro-Food Industries

Olive oil production represents an agro-industrial activity of vital economic importance for many Mediterranean countries. However, it is associated with the generation of a huge amount of by-products, both in solid and liquid forms, mainly constituted by olive mill wastewater, olive pomace, wood, leaves, and stones. Although for many years olive by-products have only been considered as a relevant environmental issue, in the last decades, numerous studies have deeply described their antioxidant, anti-inflammatory, immunomodulatory, analgesic, antimicrobial, antihypertensive, anticancer, anti-hyperglycemic activities. Therefore, the increasing interest in natural bioactive compounds represents a new challenge for olive mills. Studies have focused on optimizing methods to extract phenols from olive oil by-products for pharmaceutical or cosmetic applications and attempts have been made to describe microorganisms and metabolic activity involved in the treatment of such complex and variable by-products. However, few studies have investigated olive oil by-products in order to produce added-value ingredients and/or preservatives for food industries. This review provides an overview of the prospective of liquid olive oil by-products as a source of high nutritional value compounds to produce new functional additives or ingredients and to explore potential and future research opportunities.

Overcoming bread quality decay concerns: main issues for bread shelf life as a function of biological leavening agents and different extra ingredients used in formulation. A review

As is widely accepted, the quality decay of freshly baked bread that affects product shelf life is the result of a complex multifactorial process that involves physical staling, together with microbiological, chemical and sensorial spoilage. In this context, this paper provides a critical review of the recent literature about the main factors affecting shelf life of bread during post-baking. An overview of the recent findings about the mechanism of bread staling is firstly provided. Afterwards, the effect on staling induced by baker's yeasts and sourdough as well as by the extra ingredients commonly utilized for bread fortification is also addressed and discussed. As inclusion/exclusion criteria, only papers dealing with wheat bread and not with long-life bread or gluten-free bakery products are taken into consideration. Despite recent developments in international scientific literature, the whole mechanism that induces bread staling is far from being completely understood and the best analytical methods to be adopted to measure and/or describe in depth this process appear still debated. In this topic, the effects induced on bread shelf life by the use of biological leavening agents (baker's yeasts and sourdough) as well as by some extra ingredients included in the bread recipe have been individuated as two key issues to be addressed and discussed in terms of their influence on the kinetics of bread staling. © 2020 Society of Chemical Industry.

Are olive pomace powders a safe source of bioactives and nutrients?

BACKGROUND

The olive oil industry generates significant amounts of semi-solid wastes, namely olive pomace. Olive pomace is a by-product rich in high-value compounds (e.g. dietary fibre, unsaturated fatty acids, polyphenols) widely explored to obtain new food ingredients. However, conventional extraction methods frequently use organic solvents, while novel eco-friendly techniques have high operational costs. The development of powdered products without any extraction step has been proposed as a more feasible and sustainable approach.

RESULTS

The present study fractionated and valorized the liquid and pulp fraction of olive pomace obtaining two stable and safe powdered ingredients, namely a liquid-enriched powder (LOPP) and a pulp-enriched powder (POPP). These powders were characterized chemically, and their bioactivity was assessed. LOPP exhibited a significant amount of mannitol (141 g kg^-1 ), potassium (54 g kg^-1 ) and hydroxytyrosol derivatives (5 mg g^-1 ). POPP exhibited a high amount of dietary fibre (620 g kg^-1 ) associated with a significant amount of bound phenolics (7.41 mg GAE g^-1 fibre DW) with substantial antioxidant activity. POPP also contained an unsaturated fatty acid composition similar to that of olive oil (76% of total fatty acids) and showed potential as a reasonable source of protein (12%). Their functional properties (solubility, water-holding and oil-holding capacity), antioxidant capacity and antimicrobial activity were also assessed, and their biological safety was verified.

CONCLUSIONS

The development of olive pomace powders for application in the food industry could be a suitable strategy to add value to olive pomace and obtain safe multifunctional ingredients with higher health-promoting effects than dietary fibre and polyphenols. © 2020 Society of Chemical Industry.

Functional compounds from olive pomace to obtain high-added value foods - a review

Olive pomace, the solid by-product from virgin olive oil extraction, constitutes a remarkable source of functional compounds and has been exploited by several authors to formulate high value-added foods and, consequently, to foster the sustainability of the olive-oil chain. In this framework, the aim of the present review was to summarize the results on the application of functional compounds from olive pomace in food products. Phenolic-rich extracts from olive pomace were added to vegetable oils, fish burgers, fermented milk, and in the edible coating of fruit, to take advantage of their antioxidant and antimicrobial effects. Olive pomace was also used directly in the formulation of pasta and baked goods, by exploiting polyunsaturated fatty acids, phenolic compounds, and dietary fiber to obtain high value-added healthy foods and / or to extend their shelf-life. With the same scope, olive pomace was also added to animal feeds, providing healthy, improved animal products. Different authors used olive pomace to produce biodegradable materials and / or active packaging able to increase the content of bioactive compounds and the oxidative stability of foods. Overall, the results highlighted, in most cases, the effectiveness of the addition of olive pomace-derived functional compounds in improving nutritional value, quality, and / or the shelf-life of foods. However, the direct addition of olive pomace was found to be more challenging, especially due to alterations in the sensory and textural features of food. © 2020 Society of Chemical Industry.

Simulated digestion of an olive pomace water-soluble ingredient: relationship between the bioaccessibility of compounds and their potential health benefits

Olive pomace is a semisolid by-product with great potential as a source of bioactive compounds. Using its soluble fraction, a liquid-enriched powder (LOPP) was obtained, exhibiting a rich composition in sugars, polyphenols and minerals, with potential antioxidant, antihypertensive and antidiabetic health benefits. To validate the potential of LOPP as a functional ingredient the effect of the gastrointestinal tract on its bioactive composition and bioactivities was examined. Polyphenols and minerals were the most affected compounds; however, a significant bioaccessibility of potassium and hydroxytyrosol was verified (≥57%). As a consequence, the LOPP bioactivities were only moderately affected (losses around 50%). For example, 57.82 ± 1.27% of the recovered antioxidant activity by ORAC was serum-available. From an initial α-glucosidase inhibition activity of 87.11 ± 1.04%, at least 50% of the initial potential was retained (43.82 ± 1.14%). Regarding the initial ACE inhibitory activity (91.98 ± 3.24%), after gastrointestinal tract losses, significant antihypertensive activity was retained in the serum-available fraction (43.4 ± 3.65%). The colon-available fraction also exhibited an abundant composition in phenolics and minerals. LOPP showed to be a potential functional ingredient not only with potential benefits in preventing cardiovascular diseases but also in gut health.

Functional Ingredients from Agri-Food Waste: Effect of Inclusion Thereof on Phenolic Compound Content and Bioaccessibility in Bakery Products

Reducing food loss and waste is among the efforts to relieve the pressure on natural resources and move towards more sustainable food systems. Alternative pathways of food waste management include valorization of by-products as a source of phenolic compounds for formulation of functional foods. Bakery products may act as an optimal carrier of phenolic compounds upon fortification. The aim of this paper is to present and discuss the effect that the inclusion of functional ingredients from agri-food waste can have on phenolic content and bioaccessibility in bakery products. To this aim, methods for the recovery of phenolic compounds from agri-food waste are presented, and fortification of bakery products by waste from fruits, vegetables, and seed crops is discussed. Bioaccessibility studies on fortified food products are considered to identify gaps and needs in developing sustainable healthy foods. Fruit and vegetable by-products are among the food wastes mostly valorized as functional ingredients in bakery product formulation. Agri-food waste inclusion level has shown to correlate positively with the increase in phenolic content and antioxidant capacity. Nevertheless, further studies are required to assess bioaccessibility and bioavailability of phenolic compounds in enriched food products to estimate the potential of agri-food waste in promoting human health and well-being.

Characterization and Bio-Accessibility Evaluation of Olive Leaf Extract-Enriched "Taralli"

Olive leaves are rich in many compounds precious for human health. Due to this property, the current study was aimed to valorize the extract from this by-product in a cereal-based food, very popular all around the world, the "taralli". To this aim, ultrasound-assisted extraction was applied to dried olive leaves to obtain the extract, used as "taralli" ingredient, instead of white wine. The "taralli" with and without extract was subjected to in vitro digestion to assess the quantity of polyphenolic compounds released in the gastrointestinal tract to become available for absorption. Total content of phenols and flavonoids, as well as the antioxidant capacity, was measured on both cooked and uncooked samples, before and after digestion. In addition, High-Performance Liquid Chromatography with Diode-Array Detection (HPLC-DAD) of the three most abundant polyphenols present in olive leaf extracts, such as oleuropein, hydroxytyrosol, and verbascoside, was carried out at the three stages of the digestion process. The results showed that the substitution of white wine with olive leaf extract increased the total content of polyphenols and flavonoids and the antioxidant capacity. Bio-accessibility of the main phenolic compounds demonstrated that oleuropein resisted slightly after gastric digestion but was almost completely degraded in the intestinal phase, while hydroxytyrosol and verbascoside were not resistant to the digestion process from the gastric phase.

Effect of the Leavening Agent on the Compositional and Sensorial Characteristics of Bread Fortified with Flaxseed Cake

Health and well-being improvement is currently driving innovation in bread, using a wide variety of value-added compounds as extra ingredients, including food industry by-products in a circular economy concept. In this context, this research aimed at evaluating the effect of the fortification of bread with different percentages of flaxseed cake, comparing two leavening agents: sourdough and baker’s yeast. Sensorial, physicochemical, and nutritional properties, including pH, the main fermentative metabolites, fatty acids, total phenols, antioxidant capacity, and volatile organic compounds were determined for fortified bread. The results showed a significant improvement of nutraceutical profile of the bread fortified with flaxseed cake in a dose-dependent manner. Regardless of the leavening agent, the fortification determined a decrease of n-6:n-3 ratio, reaching the recommended value (<3) already at the 7.5% level. Furthermore, under the same fortification level, sourdough breads showed a higher level of total phenols and antiradical activity than baker’s yeast breads. Sensory profiles were instead deeply influenced by both the fortification percentage and the leavening agents. In conclusion, considering both nutritional and sensory results, the best formulation as a function of leavening agent utilized was defined as 5% and 7.5% when sourdough and baker’s yeast were used, respectively.

Olive oil by-product as functional ingredient in bakery products. Influence of processing and evaluation of biological effects

Nowadays, the strong demand for adequate nutrition is accompanied by concern about environmental pollution and there is a considerable emphasis on the recovery and recycling of food by-products and wastes. In this study, we focused on the exploitation of olive pomace as functional ingredient in biscuits and bread. Standard and enriched bakery products were made using different flours and fermentation protocols. After characterization, they were in vitro digested and used for supplementation of intestinal cells (Caco-2), which underwent exogenous inflammation. The enrichment caused a significant increase in the phenolic content in all products, particularly in the sourdough fermented ones. Sourdough fermentation also increased tocol concentration. The increased concentration of bioactive molecules did not reflect the anti-inflammatory effect, which was modulated by the baking procedure. Conventionally fermented bread enriched with 4% pomace and sourdough fermented, not-enriched bread had the greatest anti-inflammatory effect, significantly reducing IL-8 secretion in Caco-2 cells. The cell metabolome was modified only after supplementation with sourdough fermented bread enriched with 4% pomace, probably due to the high concentration of tocopherol that acted synergistically with polyphenols. Our data highlight that changes in chemical composition cannot predict changes in functionality. It is conceivable that matrices (including enrichment) and processing differently modulated bioactive bioaccessibility, and consequently functionality.