High pressure carbon dioxide (HPCD) technology applied to foods has gained a particular scientific interest considering the number of publications and patents published in the last decades. Although ...the antimicrobial effect of HPCD has been demonstrated mainly for liquid foodstuffs, very few research papers investigated the possibility to exploit the treatment on solid foods. In this concern, the main objective of the present review is to give a general survey of the published knowledge concerning the HPCD applied to solid foods. Remarks and future outlooks will be highlighted with the aim to suggest a research line to follow for future studies.
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 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.
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.
In recent years, the demand for nutritive, functional and healthy foods has increased. This trend has induced the food industry to investigate novel technologies able to produce ingredients with ...enhanced functional and physicochemical properties. Among these technologies, one of the most promising is the encapsulation based on supercritical fluids. Thanks to the inherent absence of organic solvent, the low temperature of the process to reach a supercritical state and the capacity to dissolve lipid soluble bioactives, the encapsulation with supercritical carbon dioxide represents a green technology to produce several functional ingredients, with enhanced stability, high load and tailored protection from environmental factors. Furthermore, from the fine-tuning of the process parameters like temperature, pressure and flow rate, the resulting functional ingredient can be easily designed to tailor the controlled release of the bioactive, or to reach specific levels of taste, odor and color. Accordingly, the aim of the present review is to summarize the state of the art of the techniques based on supercritical carbon dioxide for the encapsulation of bioactive compounds of food interest. Pros and cons of such techniques will be highlighted, giving emphasis to their innovative aspects that could be of interest to the food industry.
Antimicrobial agents are substances that, when present at low concentrations, can delay microbial growth. For many years, several powerful antimicrobial substances have been synthetized. However, ...because of their significant side effects, there is a growing interest nowadays to find natural alternatives to the synthetic one. The present study aims to recover extracts with antimicrobial activity from
Picea abies
residues using two different extraction technologies, respectively, Soxhlet and supercritical carbon dioxide. Their antimicrobial activity was tested on the growth of
Enterococcus faecalis
and
Streptococcus thermophilus.
Isothermal calorimetry was used as a technique to quantify the antimicrobial effect of the extracts. The heat flow curves, obtained during the microbial growth, were fitted by a modified Gompertz function obtaining the lag time (
λ
) and the maximum growth rate (
μ
max
) parameters. High-resolution mass spectrometry was used to identify the phenolic compounds responsible for the antimicrobial activity of the extracts. Regardless to the technology used, both extracts showed similar antimicrobial activity. For both microbial strains, the addition of the extract induced longer lag times (
λ
), while the maximum growth rate (
μ
max
) decreased.
S. thermophilus
showed a higher resistance compared to
E. faecalis
suggesting a different capacity to metabolize the substrate in the presence of
Picea abies
extracts. Catechin, dihydroquercetin, astringin and isorhapontin were the identified phenolic compounds responsible for such effect. In conclusion, the results of this study provided an exciting potential for the future in light of the shift away from artificial preservatives and the trend toward natural alternative compounds coming from sustainable sources.
This study aims to investigate the effect of essential oils extracted from wood residues of
on the growth of
. The essential oils were extracted by supercritical carbon dioxide, leading to a yield of ...3.4 ± 0.5% (
/
) in 120 min. The antimicrobial effect was tested at 37 °C by isothermal calorimetry. The heat-flow (dq/dt vs. time) was integrated to give a fractional reaction curve (α vs. time). Such curves were fitted by a modified Gompertz function to give the lag-time (λ) and the maximum growth rate (µmax) parameters. The results showed that λ was linearly correlated with
concentration (λ = 1.4 h/log (CFU/mL), R
= 0.997), whereas µmax was invariant. Moreover, the overall heat was nearly constant to all the dilutions of
. Instead, when the essential oil was added (with concentrations ranging from 1 to 5 mg/L) to a culture of
(10
CFU/mL), the lag-time increased from 14.1 to 33.7 h, and the overall heat decreased from 2120 to 2.37 J. The results obtained by the plate count technique were linear with the lag-time (λ), where (λ = -7.3 × log (CFU/mL) + 38.3, R
= 0.9878). This suggested a lower capacity of
to metabolize the substrate in the presence of the essential oils. The results obtained in this study promote the use of essential oils from wood residues and their use as antimicrobial products.
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