Bioactive Components in Fermented Foods and Food By-Products

Food fermentation is one of the most ancient processes of food production that has historically been used to extend food shelf life and to enhance its organoleptic properties. However, several studies have demonstrated that fermentation is also able to increase the nutritional value and/or digestibility of food. Firstly, microorganisms are able to produce huge amounts of secondary metabolites with excellent health benefits and preservative properties (i.e., antimicrobial activity). Secondarily, fermented foods contain living organisms that contribute to the modulation of the host physiological balance, which constitutes an opportunity to enrich the diet with new bioactive molecules. Indeed, some microorganisms can increase the levels of numerous bioactive compounds (e.g., vitamins, antioxidant compounds, peptides, etc.). Moreover, recent advances in fermentation have focused on food by-products; in fact, they are a source of potentially bioactive compounds that, after fermentation, could be used as ingredients for nutraceuticals and functional food formulations. Because of that, understanding the benefits of food fermentation is a growing field of research in nutrition and food science. This book aims to present the current knowledge and research trends concerning the use of fermentation technologies as sustainable and GRAS processes for food and nutraceutical production

Nutritional and Functional Advantages of the Use of Fermented Black Chickpea Flour for Semolina-Pasta Fortification

Pasta represents a dominant portion of the diet worldwide and its functionalization with high nutritional value ingredients, such as legumes, is the most ideal solution to shape consumers behavior towards healthier food choices. Aiming at improving the nutritional quality of semolina pasta, semi-liquid dough of a Mediterranean black chickpea flour, fermented with Lactiplantibacillus plantarum T0A10, was used at a substitution level of 15% to manufacture fortified pasta. Fermentation with the selected starter enabled the release of 20% of bound phenolic compounds, and the conversion of free compounds into more active forms (dihydrocaffeic and phloretic acid) in the dough. Fermented dough also had higher resistant starch (up to 60% compared to the control) and total free amino acids (almost 3 g/kg) contents, whereas antinutritional factors (raffinose, condensed tannins, trypsin inhibitors and saponins) significantly decreased. The impact of black chickpea addition on pasta nutritional, technological and sensory features, was also assessed. Compared to traditional (semolina) pasta, fortified pasta had lower starch hydrolysis rate (ca. 18%) and higher in vitro protein digestibility (up to 38%). Moreover, fortified cooked pasta, showing scavenging activity against DPPH and ABTS radicals and intense inhibition of linoleic acid peroxidation, was appreciated for its peculiar organoleptic profile. Therefore, fermentation technology appears to be a promising tool to enhance the quality of pasta and promote the use of local chickpea cultivars while preventing their genetic erosion.Spanish Ministry of Economy and Competitiveness (MINECO) RYC-2015-1879

Antioxidant and Antimicrobial Activity of Hydroethanolic Leaf Extracts from Six Mediterranean Olive Cultivars

Phenolic profiles, antioxidant, and antimicrobial activities of hydroethanolic olive leaf extracts from six Mediterranean olive cultivars (Croatian: Lastovka, Levantinka, Oblica; Italian: Moraiolo, Frantoio, Nostrana di Brisighella) were investigated. As expected, various distributions of phenolic levels were observed for each cultivar and the total phenolic content showed high variability (ranging from 4 to 22 mg GAE/g of dry extract), with the highest amount of phenolics found in the Oblica sample, which also provided the highest antiradical (ORAC) and reducing activity (FRAP). The screening of individual compounds was performed by HPLC-PDA-ESI-QTOF-MS and the main detected compounds were oleuropein, hydroxytyrosol, oleoside/secologanoside, verbascoside, rutin, luteolin glucoside, hydroxyoleuropein, and ligstroside. While the antioxidant activity of the samples was relatively high, they showed no bactericidal and bacteriostatic activity against E. coli and S. Typhimurium; weak activity against Staphylococcus aureus, Bacillus cereus, and Listeria innocua; and inhibitory effects against Campylobacter jejuni at 0.5 mg dry extract/mL. The obtained results support the fact that olive leaf extracts, and especially those from the Oblica cultivar, could potentially be applied in various industries as natural preservatives and effective and inexpensive sources of valuable antioxidants.PRIMA program under project BioProMedFood 1467European CommissionMCIN/AEI RTI2018-099835-A-I0

Development of an Effective Sonotrode Based Extraction Technique for the Recovery of Phenolic Compounds with Antioxidant Activities in Cherimoya Leaves

The leaves of Annona cherimola Mill (cherimoya) are a potential source of phenolic compounds that have been shown to have beneficial properties. Therefore, this study focuses on establishing an ultrasonic-assisted extraction of phenolic compounds in cherimoya leaves using a sonotrode. For that purpose, a Box-Behnken design based on a response surface methodology (RSM) was used to optimize factors, such as amplitude, extraction time and solvent composition to obtain the maximum content of phenolic compounds by HPLC-MS and the maximum in-vitro antioxidant activity by DPPH, ABTS and FRAP assays in ‘Fino de Jete’ cherimoya leaves. The optimal conditions were 70% amplitude, 10 min and 40:60 ethanol/water (EtOH/H2O) (v/v). The results obtained under these optimum conditions by using a sonotrode were compared with those from an ultrasonic bath; briefly, recovery of phenolic compounds by sonotrode was 2.3 times higher than a bath. Therefore, these optimal conditions were applied to different varieties ‘Campas’, ‘Fino de Jete’ and ‘Negrito Joven’ harvested in the Tropical Coast of Granada (Spain). A total of 39 phenolic compounds were determined in these cherimoya leaf extracts, 24 phenolic compounds by HPLC-MS and 15 proanthocianidins by HPLC-FLD. 5-p-coumaroylquinic acid, lathyroside-7-O- -l-rhamnopyranoside and quercetin hexose acetate were first identified in cherimoya leaves. The most concentrated phenolic compounds were the flavonoids, such as rutin and quercetin hexoside and proanthocyanidins including monomers. Almost no significant differences in the phenolic content in these cultivars were found (11–13 mg/g d.w. for phenolic compounds and 11–20 mg/g d.w. for proanthocyanidins). In addition, sonotrode ultrasonic-assisted extraction has been shown to be an efficient extraction technique in the phenolic recovery from cherimoya leaves that could be implemented on an industrial scale.MCIN/AEI/FEDER "Una manera de hacer Europa" RTI2018-099835-A-I0

Comparison between Ultrasonic Bath and Sonotrode Extraction of Phenolic Compounds from Mango Peel By-Products

Phenolic compounds present in mango peel byproducts have been reported to have several beneficial health properties. In this study, we carried out an optimization of phenolic compounds using ultrasound-assisted extraction via ultrasonic bath and sonotrode. To optimize the variables of extraction, a Box–Behnken design was used to evaluate the best conditions to obtain high total phenolic compound extraction and high antioxidant activity evaluated by different methods (DPPH, ABTS, and FRAP). The optimal ultrasonic bath conditions were 45% ethanol, 60 min, and 1/450 ratio sample/solvent (w/v) whereas optimal sonotrode conditions were 55% ethanol, 18 min, and 65% amplitude. The extracts obtained at the optimal conditions were characterized by HPLC–ESI-TOF-MS. A total of 35 phenolic compounds were determined and, to our knowledge, several of them were tentatively identified for the first time in mango peel. The samples were composed mainly by phenolic acids derivatives, specifically of galloylglucose and methylgallate, which represented more than 50% of phenolic compounds of mango peel byproducts. In conclusion, sonotrode is a valuable green technology able to produce enriched phenolic compound extracts from mango peel byproducts that could be used for food, nutraceutical, and cosmeceutical applications.MCIN/AEI/FEDER "Una manera de hacer Europa" RTI2018-099835-A-I0

Phenolic Profile, Antioxidant Activity and Amino Acid Composition of Moringa Leaves Fermented with Edible Fungal Strains

Solid-state fermentation (SSF) is widely recognised as a technique to increase the bioactive potential and nutritional value of plant materials. However, the effect of this biotreatment differs for individual substrates. This study aimed to evaluate the impact of SSF with filamentous fungi (Rhizopus, Aspergillus, and Neurospora) on a moringa leaf phenolic profile, antioxidant activity, and amino acid composition. A total of 43 phenolic compounds were determined in the dried leaves analysed by HPLC-ESI-TOF-MS. The leaves contained 11.79 mg/g of free phenolics: flavonols (80.6%, mainly quercetin and kaempferol glycosides), hydroxycinnamic acid derivatives (12.3%), vitexin and vicenin (6.9%), and a small amount of lignan (isolariciresinol isomers). The result of the 1-day fermentation was a slight enhancement in the concentration of individual free phenolics (flavones) and the antioxidant activity of the leaves. However, extending the incubation period caused a significant decrease in those parameters and cannot be recommended for obtaining a food fortificant from moringa leaves. In contrast, the 3-day fermentation with N. intermedia led to a 26% average accumulation of individual amino acids. Therefore, the SSF with Neurospora can be a promising method for improving the nutritional composition of moringa leaves and needs further investigation.MCIN/AEI RTI2018-099835-A-I0

Choline chloride derivative-based deep eutectic liquids as novel green alternative solvents for extraction of phenolic compounds from olive leaf

In the presented study, a new methodology based on the use of deep eutectic solvents (DESs) and microwave-assisted extraction (MAE) and subsequent analysis by HPLC-DAD-ESITOF- MS was proposed for the extraction of phenolic compounds from olive leaf. Nine different DESs, using choline chloride as hydrogen bond acceptor in combination with different hydrogen bond donors (four polyalcohols, three organic acids, one sugar and urea), were firstly scanned. A total of 48 phenolic compounds were identified in the olive leaf using HPLC-DAD-ESI-TOF-MS. Experimental results and multivariate data analysis pointed to choline chloride-ethyleneglycol as being the most effective within the tested DESs, showing extraction yields similar to those exhibited by conventional solvents. A Box-Behnken Design and response surface methodology were applied with the aim to optimize the main parameters involved in the extraction process. The optimal extraction conditions were 79.6 ºC of temperature, 43.3% of water and 16.7 min of irradiation time. Correlation coefficients (R2> 0.98) indicated a good relationship between experimental data and the fitted quadratic term models. Results indicated that DESs could be a sustainable alternative to traditional solvents for the extraction of bioactive compounds among many other applications.Thanks to the Spanish Ministry of Economy and Competitiveness (MINECO) (AGL2015-67995-C3-2-R) and the Andalusian Regional Government Council (P11-CTS-7625). M.E. Alañón also thanks to Ministry of Education and Competitiveness for the postdoctoral contract Juan de la Cierva-Incorporación (IJCI-2014-21664)

Solid State Fermentation of Olive Leaves as a Promising Technology to Obtain Hydroxytyrosol and Elenolic Acid Derivatives Enriched Extracts

Extraction of valuable bioactive compounds from olive leaves is a hot topic and the use of sustainable and green technologies is mandatory in terms of circular economy. In this way, the use of fermentation technologies showed very interesting results in terms of phenolic compound recovery. Because of that in this work the use of solid state fermentations, as valuable tool to improve the phenolic extraction has been checked. Aspergillus oryzae (in mycelium and spore form), Aspergillus awamori and Aspergillus niger were used as fermentation microrganisms. Phenolic compounds were determined by HPLC-ESI-TOF-MS and, to our knowledge, new compounds have been tentatively identified in olive leaves. Fermentation using mycelium of Aspergillus awamori, Aspergillus niger and Aspergillus oryzae were effective to increase both hydroxytyrosol and elenolic acid derivatives whereas the use of spores of Aspergillus oryzae caused a loss of hydroxytyrosoyl derivatives, contrary the content of elenolic derivatives are comparable with the other fermentation treatments and higher than control. The proposed fermentation processes using the mycelium of Aspergillus awamori, Aspergillus niger and Aspergillus oryzae lead to an increase the hydroxytyrosyl and elenolic acid derivatives and could be used at industrial scale to obtain enriched extracts.Ministry of Science and Innovation, Spain (MICINN) Instituto de Salud Carlos III Spanish Government RTI2018-099835-A-I00 MCIN/AEI/10.13039/501100011033/FEDE

A Box-Behnken Design for Optimal Green Extraction of Compounds from Olive Leaves That Potentially Activate the AMPK Pathway

The author B.M.-G. is grateful to the National Youth Guarantee System for the grant for young research personnel. Also, the authors are grateful to the University of Granada for a “Contrato Puente” postdoctoral contract (S.P.-M.).Olive leaves contain bioactive compounds that have been shown to activate AMP-activated protein kinase (AMPK), which decreases intracellular lipid accumulation. Microwave-assisted extraction (MAE) is a green extraction technique that is frequently used in the recovery of phenolic compounds from plants. Thus, in this study, a Box-Behnken design was used to optimize MAE conditions such as temperature, percentage of ethanol and extraction time to obtain the maximum content of total compounds and compounds that activate AMPK. To this end, all extracts were characterized by High-Performance Liquid Chromatography Coupled to Electrospray Ionization Time-of-Flight Mass Spectrometry (HPLC-ESI-TOF-MS). The optimum conditions to obtain the highest content of total compounds were 123 ◦C, 100% of ethanol/water (v/v) and 23 min, whereas the optimum conditions for the highest amount of compounds that activate AMPK were 111 ◦C, 42% of ethanol/water (v/v) and 23 min. Thus, a multi-analysis by desirability was carried out to establish MAE optimal conditions for both responses. The optimum conditions were 111 ◦C, 100% EtOH and 23 min with a desirability of 0.97, which means that the responses are close to their individual optimal values. As a result, the olive leaf extract obtained at these optimal MAE conditions has great potential to be effective in the treatment of obesity.Spanish Ministry of Economy and Competitiveness (MINECO) AGL2015-67995-C3-2Ministry of Science, Innovation and Universities RTI2018-096724-B-C22Ministry of Economy, Knowledge, Business and University of the Junta de Andalucia B-AGR-466-UGR1