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Introduction: Encapsulation of the bioactive ingredients in biodegradable and edible polymers is an alternative novel application method to keep these kind of natural products stable. Objective: The purpose is to optimize the encapsulation system of olive leaf extract by spray drying method, and to apply the products into a model food. Methods: Olive leaf extract was encapsulated in arabic gum/maltodextrin blend by spray drying method. Combined design approach under I‐optimal design type was used to optimize the system. Characterisation studies under moisture content, water activity, solubility, bulk density, tapped density, Carr index, particle size distribution, powder morphology and glass transition temperature were applied to the microparticles obtained under optimum conditions. The bioavailability of the encapsulated active material was tested by in vitro gastrointestinal digestion. Furthermore, microparticles produced under optimum conditions were also evaluated for a potential functional food application. Results: The optimum conditions were achieved by arabic gum/maltodextrin (3.7:6.3) with 10% (w/v) in the mixture of wall material and active material under 165.5°C to achieve maximum encapsulation efficiency (86.92%), encapsulation yield (71.32%) and antioxidant activity (5.74 mg Trolox equivalent antioxidant capacity/g dry microparticle). Conclusions: Olive leaf extract encapsulated in arabic gum/maltodextrin may be a good alternative additive to prevent the lipid oxidation in fat‐containing food products as well as improvement of the product quality by functional properties. The optimum conditions were achieved by Arabic gum: maltodextrin (3.7:6.3) with 10% (w/v) in the mixture of wall material and active material under 165.5°C to achieve maximum encapsulation efficiency (86.92%), encapsulation yield (71.32%) and antioxidant activity (5.74 mg‐TEAC/g‐DM). 67.97% of the TPC released from the microcapsules in the intestinal system than gastric system, while the release in the gastric fluid was 52.55%. The stability of the treated sunflower oil with microparticles containing olive leaf extract was improved against oxidation. [ABSTRACT FROM AUTHOR]

Introduction: The recovery process for bioactives from discarded by‐products of the winemaking industry is of great value considering both environmental and economic aspects. Objective: The goal of this study is to investigate the extraction of phenolic antioxidants from grape (Vitis vinifera) seeds by means of carboxylic acid‐based deep eutectic solvents (DESs) in order to propose an environmentally friendly method based on a multivariate optimization approach. Material and Methods: Carboxylic acid‐based DESs were designed with several molar ratios (1/1, 1/2, and 2/1). Two polyols (glycerol and ethylene glycol) were used as hydrogen bond donors, while formic acid, acetic acid, and propionic acid were selected as hydrogen bond acceptors. The process parameters (water content, extraction time, and solid mass) were analyzed to optimize the process through Box–Behnken design with response surface method, after determination of the best combination for the highest total phenolic content (TPC) and the antioxidant activity yields. Results: The maximum TPC yield (153.17 ± 0.003 mg‐GAE/g‐GS) and antioxidant activity yield (82.26 ± 0.004 mg‐GAE/g‐GS) were achieved by 50% water addition into the DES (ethylene glycol/acetic acid, 1/1), 85 sec extraction time, and 0.1 g grape seed. Several polyols and carboxylic acids were designed with different molar ratios to produce deep eutectic solvents. The best formulation was achieved by ethylene glycol/acetic acid (1/1, molar ratio) based on the highest phenolic content. Homogenizer‐assisted extraction of the phenolic antioxidants from grape seeds were optimized based on Box‐Behnken design. The maximum TPC (153.17 ± 0.003 mg‐GAE/g‐GS) and antioxidant activity (82.26 ± 0.004 mg‐GAE/g‐GS) were achieved by 50% water addition into the DES (ethylene glycol/acetic acid, 1/1), 85 sec time and 0.1 g grape seed. [ABSTRACT FROM AUTHOR]

Introduction: Waste by‐products of the juice industry appear valuable for the circular economy concept, considering that the peel accounts for almost half of the total fruit weight. Therefore, the recovery of these highly valuable components from relevant biowaste has become a very interesting research topic. Objective: The current study aims to develop an extraction process integrated with hydrophobic deep eutectic solvent (DES) based on statistical experimental design approach. Material and methods: Homogenizer‐assissted extraction (HAE) was used to recover the citrus extract rich in limonene (the main component of the volatile mixture) from lemon peels. Menthol‐based deep eutectic mixtures were accompanied by carboxylic acids (formic, acetic, and propionic acids). Optimization continued on the combination that gave the highest efficiency (in terms of limonene content) among the solvents prepared at different molar ratios (1/1, 1/2, and 2/1). Process parameters were analyzed to optimize the process through central composite design with response surface method (RSM). D‐Limonene yield was quantified with gas chromatography–mass spectrometry (GC‐MS) with solid‐phase microextraction (SPME) technique. The quality of the lemon peel extracts was also evaluated with respect to in vitro bioactivity assays (phenolic content and 2,2‐diphenyl‐1‐picrylhydrazyl [DPPH] free radical scavenging activity). Results: The maximum yield (3.80 mg‐limonene per g fresh sample) was achieved by 2 mg solid/30 mL DES, ~53 sec, and ~8500 rpm. Statistically most effective variable was identified as solid mass, followed by second powers of mixing speed and extraction time at p < 0.0001. The menthol/acetic acid mixture (1/2, molar ratio) yielded the best (almost twice in terms of bioactive properties). The principal component of the hydrophobic extract was determined as D‐limonene by GC‐MS. The maximum yield (3.80 mg‐limonene/g‐FS) was achieved by 2 mg solid/30 mL DES, ~53 sec, and ~8500 rpm. The validation study (the difference between the actual and the predicted < 2%) confirmed the reliability of the optimization study of the Central Composite design through Response Surface Methodology. [ABSTRACT FROM AUTHOR]