Lipid-soluble bioactives are important nutrients in foods. However, their addition in food formulations, is often limited by limited solubility and high tendency for oxidation. Lipid-soluble ...bioactives, such as vitamins A, E, D and K, carotenoids, polyunsaturated fatty acids (PUFA) and essential oils are generally dispersed in water-based solutions by homogenization. Among the different homogenization technologies available, nanoemulsions are one of the most promising. Accordingly, this review aims to summarize the most recent advances in nanoemulsion technology for the encapsulation of lipid-soluble bioactives. Modern approaches for producing nanoemulsion systems will be discussed. In addition, the challenges on the encapsulation of common food ingredients, including the physical and chemical stability of the nanoemulsion systems, will be also critically examined.
The reaction kinetics of antioxidants with free radicals is crucial to screen their functionality. However, studying antioxidant-radical interactions is very challenging for fast electron-donor ...substances, such as ascorbic acid, because the reaction ends in a few seconds. Accordingly, this work proposes a rapid and sensitive method for the determination of the absolute rate constant of the reaction between fast antioxidants and DPPH
. The method consists of a stopped-flow spectrophotometric system, which monitors the decay of DPPH
during its interaction with antioxidants. A kinetic-based reaction mechanism fits the experimental data. Kinetic parameters include a second order kinetics (k
) and, depending on the type of antioxidant, a side reaction (k
). Ascorbic acid was the fastest antioxidant (k
= 21,100 ± 570 M
s
) in comparison with other eleven phenols, showing k
values from 45 to 3070 M
s
. Compounds like catechin, epicatechin, quercetin, rutin, and tannic, ellagic and syringic acids presented a side reaction (k
from 15 to 60 M
s
). Among seven fruit juices, strawberry was the fastest, while red plum the slowest. Overall, the proposed kinetic-based DPPH
method is simple, rapid, and suitable for studying the activity and capacity of different molecules, and food samples rich in fast antioxidants, like fruit juices.
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•Thermal behavior of glycerolyzed oils strongly depends on acylglycerides fractions.•Lipid structuring through glycerolysis improved the stability of W/O ...emulsions.•Glycerolysis-structured oils could potentially replace saturated fats in foods.
Enzymatic glycerolysis is a biotechnological process for structuring vegetable oils. This study investigates the kinetics of glycerolysis of peanut oil and explores the potential of the resulting structured oil to enhance the physical stability of water-in-oil emulsions. Using a 1:1 glycerol-to-oil molar ratio and 4 % lipase B from Candida antarctica as a catalyst, the reaction was conducted at 65 °C with stirring at 400 rpm. Acylglyceride fractions changes were quantified through NMR and DSC. Fat crystal formation was observed using scanning electron microscopy. The results revealed a first-order decay pattern, converting triglycerides into monoacylglycerides and diacylglycerides in less than 16 h. Subsequently, water-in-oil emulsions prepared with glycerolized oil showed augmented stability through multiple light scattering techniques and visual assessment. The structured oils effectively delayed phase separation, highlighting the potential of glycerolysis in developing vegetable oil-based emulsions with improved functional properties and reduced saturated fatty acid content.
The use of alternative protein sources is widely investigated nowadays to ensure a sufficient and nutritious diet for the society. Among different possibilities, insects are currently considered a ...sustainable and efficient alternative to study more in deep. To this purpose, the present work investigates the use of hot melt extrusion to produce pellets made of insect flour (Hermetia illucens) used alone or mixed in different ratios (1:1 to 1:3) with corn flour. The samples were analysed in terms of physical properties as moisture content, color, water activity, and functional properties as water absorption index, water solubility index, oil sorption and viscosity. The results of the physical properties showed that the color of the pellets was greatly influenced by the blends used: dark brown for insect flour and yellowish for corn flour. Pure insect flour pellets had the lowest water absorption index (2.1 ± 0.3%) and the highest water solubility index (16.8 ± 0.3). The viscoamilographic profiles showed that the addition of the insect flour affected the pasting properties of the formulations. Overall, the results indicate the possibility to include insect flour during the extrusion process as potential source of proteins.
•Insect flour showed interesting characteristics as source of proteins and fats exploitable for feed.•Insect flour was used alone or mixed with corn in different ratios to prepare pellets by hot melt extrusion.•Extrudates of pure insect flour had the lowest water absorption index and the highest water solubility index.•The presence of insect flour in the corn blends affected the pasting properties of the extrudates.
This work aims to determine the antioxidants activity of individual antioxidants and natural extracts by isothermal calorimetry. The proposed method is an adaptation of the “
inhibited autoxidation ...method
”. It consists of the monitoring of the heat-flow signal evolved during the autoxidation of styrene, in the presence of 2,2′-azobis(isobutyronitrile) as radical initiator, with individual antioxidants or plant extracts as inhibitors, and under isothermal conditions (303 K). The resulting calorimetric traces were transformed in conversion fractions over time. The antioxidant activity was expressed with the initial slope of the inhibited period of styrene autoxidation. Also, the induction period observed at the onset of the uninhibited styrene autoxidation leaded the stoichiometry number of the reaction between antioxidants and free radicals. The approach was very simple, and it allowed to rank individual antioxidants (
α
-tocopherol > > gallic acid = quercetin > syringic acid > > synaptic acid > 4-hydroxybenzoic acid) and plant extracts (
Olea europea
>
Melissa officinalis
>
Fraxinus excelsior
> >
Papaver rhoeas
), based on their ability to decrease the conversion rate of styrene autoxidation. The results on plant extracts were critically compared with those from the DPPH assay. Differently to the many antioxidant assays widely used nowadays, the proposed approach has the merit to test the activity of micromolar quantities of antioxidants to inhibit the autoxidation of a large excess of an oxidizable substrate, whose oxidation is induced by a constant rate of free radicals formation under well controlled and reproducible experimental conditions.
Phenolic compounds are an important group of organic molecules with high radical scavenging, antimicrobial, anti-inflammatory, and antioxidant properties. The emerging interest in phenolic compounds ...in food products has led to the development of various analytical techniques for their detection and characterization. Among them, the coulometric array detector is a sensitive, selective, and precise method for the analysis of polyphenols. This review discusses the principle of this method and recent advances in its development, as well as trends in its application for the analysis of phenolic compounds in food products, such as fruits, cereals, beverages, herbs, and spices.
•Fermentation strongly increased the antioxidant activity of avocado puree (AP)•Water and hexane soluble extracts showed the highest antioxidant activity.•Fermentation modified the profile of ...bioactive compounds of AP.•Oleic and linoleic acids were highly metabolized by L. plantarum AVEF17.•Levels of mono, di-, and tri-hydroxy-octadecenoic acids increased in fermented AP.
This study investigated the capability of selected autochthonous lactic acid bacteria to enrich the portfolio of bioactive compounds of avocado fruit (Persea americana Mill.), with the perspective of producing dietary supplements or pharmaceutical preparations. Fermented avocado puree resulted in high levels of total free amino acids. Fermentation also led to a marked increase of antioxidant activity, with the highest levels found in water and hexane soluble extracts. Bio-converted phenolic compounds and fatty acids derivatives resulting from bacterial metabolism were likely responsible for the increased antioxidant activity. Fermentation caused the fortification of avocado puree with some hydroxy fatty acids, which deserved marked attention due to their health-promoting activities. Oleic and linoleic acids were highly metabolized by Lactobacillus plantarum AVEF17, leading to high levels of mono, di-, and tri-hydroxy-octadecenoic acids.
In recent years, there has been a growing interest in utilizing natural antioxidants as alternatives to synthetic additives in food products. Apples and apple by-products have gained attention as a ...potential source of natural antioxidants due to their rich phenolic content. However, the extraction techniques applied for the recovery of phenolic compounds need to be chosen carefully. Studies show that ultrasound-assisted extraction is the most promising technique. High yields of phenolic compounds with antioxidant properties have been obtained by applying ultrasound on both apples and their by-products. Promising results have also been reported for green technologies such as supercritical fluid extraction, especially when a co-solvent is used. Once extracted, recent studies also indicate the feasibility of using these compounds in food products and packaging materials. The present review aims to provide a comprehensive overview of the antioxidant properties of apples and apple by-products, their extraction techniques, and potential applications in food products because of their antioxidant or nutritional properties. The findings reported here highlight the proper utilization of apples and their by-products in food to reduce the detrimental effect on the environment and provide a positive impact on the economy.
The work aimed to encapsulate oils recovered from brewer’s spent grain by particles from gas saturated solutions technique using supercritical carbon dioxide as solvent and polyethylene glycol as ...wall material. The process conditions (pressure and temperature) and the wall material content were tested to produce an ingredient with enhanced physical properties and oxidative stability. Among the applied pressures (10, 20, 30, and 35 MPa), temperatures (45 and 55 °C) and oil to polyethylene glycol mixing ratios (1:5; 1:3, 1:2.5 and 1:2), the highest encapsulation efficiency was obtained at 20 MPa, 55 °C with an oil to polyethylene glycol mixing ratio equal to 1:3. With such conditions, the particles reported 73.5 ± 1.5% of encapsulated oil, with 58.1 ± 2.8% of the powder showing a mean diameter equal to 375 μm. The bulk and tapped densities were equal to 0.35 ± 0.01 and 0.38 ± 0.01 g · cm
−3
, while the wettability resulted of 3.2 ± 0.01 min. Furthermore, the encapsulated oil was oxidative stable up to 130 ± 3.2 h at 40 °C, as measured by isothermal calorimetry and peroxide value. The findings showed the potentials of particles from gas saturated solutions technique for the production of an ingredient for food, cosmetic and pharmaceutical applications.
This work explores the functionality of oils from brewer’s spent grain by supercritical fluid extraction. The process was performed at 20 and 30 MPa, and 40 and 50 °C without and with ethanol as ...co-solvent in percentages equal to 4 and 8%. Supercritical fluid extraction was compared with Soxhlet using hexane as solvent. The extracts were characterized for their antioxidant capacity by 2,2-diphenyl-1-picryhydrazyl radical (DPPH) assays, total phenolic content by Folin–Ciocalteu assay, fatty acid profile by GC-FID, and oxidative stability by isothermal calorimetry. Moreover, their capacity to retard the oxidation of linseed oil was also studied. Samples from Soxhlet and supercritical carbon dioxide (30 MPa, 50 °C, and 8% of ethanol) showed the highest yields (6.1 ± 0.3% and 6.5 ± 0.1%,
w
/
w
), recovery (78.3 ± 2.1% and 81.3 ± 1.8%,
w
/
w
), total phenolic contents (28.3 ± 0.5 and 26.2 ± 0.3 mg GAE/g of sample), and antioxidant activity (16.7 ± 0.1 and 14.2 ± 0.1 mg TEA/g of sample). The fatty acid composition of brewer’s spent oil extracted by SFE was similar to that extracted by Soxhlet. The same extracts also reported the highest oxidative stability and ability to slow down linseed oil oxidation.
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