Optimisation of olive oil extraction by means of enzyme processing aids using response surface methodology

Optimized Ultrasound-Assisted Enzymatic Extraction of Phenolic Compounds from Rosa canina L. Pseudo-Fruits (Rosehip) and Their Biological Activity

Two techniques, namely, optimized ultrasound-assisted extraction (UAE) and enzyme-assisted extraction (EAE), were used to promote the extraction of phenolic compounds from the pseudo-fruits of Rosa canina L. (RC). For UAE, an optimization process based on the design of experiment (DoE) principles was used for determining the dependence between three variables (i.e., time of extraction, ultrasound amplitude, and the material-to-water ratio) and the total phenolic content of the samples. For EAE, a 2:1:1 pectinase, cellulase, and hemicellulase enzymatic blend was used as pre-treatment for optimized UAE, inducing a higher total phenolic content. The untargeted phenolic profiling approach revealed a great abundance of lower molecular weight phenolics (1.64 mg Eq./g) in UAE-RC extracts, whilst gallic acid (belonging to hydroxybenzoic acid derivatives) was the most abundant individual compound of both extracts. The unsupervised multivariate statistics clearly discriminated the impact of enzymatic pre-treatment on the phenolic profile of RC pseudo-fruits. Finally, Pearson’s correlation coefficients showed that anthocyanins, phenolic acids, and tyrosol derivatives were those compounds mostly correlated to the in vitro antioxidant potential of the extracts, whilst negative and significant (p < 0.05) correlation coefficients were recorded when considering the enzymatic inhibition activities. The highest enzyme-inhibitory activity has been identified against α-glucosidase, which indicates an antidiabetic effect.

Mixed pretreatment based on pectinase and cellulase accelerates the oil droplet coalescence and oil yield from olive paste

Commercial enzymatic pretreatment is being classically used for enhancing the oil extraction yield in the olive oil industry in China. Nevertheless, the mechanism is not yet clearly defined. The aim was to study the action of pectinase and cellulase for improving the oil yield from the aspects of oil droplets coalescence and rheological properties changes of olive paste during malaxation process. From confocal laser scanning microscopy imaging, the bound oil droplets were released and gradually coalesced into larger droplets, eventually formed a continuous oil phase with enzymatic pretreatment. Furthermore, the mixed enzymatic pretreatment effectively decreased viscosity of the olive pastes and promoted the depolymerization and solubilization of pectic polymers involved in the cell-cell adhesion, thus further enhanced the oil extraction yield from 7.15 % to 11.68 % (w/w). Finally, the mixed enzymatic pretreatment improved the droplet release and coalescence, reduced the viscosity of olive paste, and increased the oil yield.

Evaluation of yield and quality properties of Elaeagnus mollis oil produced by ultrasound-assisted solvent enzymatic extraction

To improve the extraction efficiency and quality, ultrasound-assisted solvent enzymatic extraction (UASEE) method was applied to extract oil from Elaeagnus mollis Diels. The soxhlet extraction (SE) and cold pressing (CP) were carried out to be compared with UASEE. The optimal UASEE conditions were liquid–solid ratio of 11.6 mL/g, enzyme amount of 1.1%, and ultrasound power of 583 W, which gave by Plackett–Burman and Box–Behnken design. Under optimum conditions, the oil yield of 43.35 ± 0.26% was reached, which was similar to that of SE (43.02 ± 0.77%). The oil obtained by UASEE is more desirable than that of SE, but similar with CP, especially on unsaturated fatty acids content and total tocopherol content. Overall, UASEE is a potential alternative to traditional methods for the efficient extraction of E. mollis oil for its higher oil yield and better quality.

Characterization and Demulsification of the Oil-Rich Emulsion from the Aqueous Extraction Process of Almond Flour

The aqueous extraction process (AEP) allows the concurrent extraction of oil and protein from almond flour without the use of harsh solvents. However, the majority of the oil extracted in the AEP is present in an emulsion that needs to be demulsified for subsequent industrial utilization. The effects of scaling-up the AEP of almond flour from 0.7 to 7 L and the efficiency of enzymatic and chemical approaches to demulsify the cream were evaluated. The AEP was carried out at pH 9.0, solids-to-liquid ratio of 1:10, and constant stirring of 120 rpm at 50 °C. Oil extraction yields of 61.9% and protein extraction yields of 66.6% were achieved. At optimum conditions, enzymatic and chemical demulsification strategies led to a sevenfold increase (from 8 to 66%) in the oil recovery compared with the control. However, enzymatic demulsification resulted in significant changes in the physicochemical properties of the cream protein and faster demulsification (29% reduction in the incubation time and a small reduction in the demulsification temperature from 55 to 50 °C) compared with the chemical approach. Reduced cream stability after enzymatic demulsification could be attributed to the hydrolysis of the amandin α-unit and reduced protein hydrophobicity. Moreover, the fatty acid composition of the AEP oil obtained from both demulsification strategies was similar to the hexane extracted oil.

Effects of treatment temperatures on redox potential and sensory evaluation of different spices and herbs applied to cooked pork sausages

BACKGROUND

This study aimed to investigate the effects of treatment temperatures (22, 78, 100 °C) on the antioxidant activity of 13 types of dried ground spices and herbs (black mustard, black pepper, blackberries, onion, cumin, galangal, lemon balm, lovage, marjoram, oregano, parsley, rosemary and watercress) through measurements of redox potential. Four different combinations of spices and herbs were created and applied to cooked pork sausages, then sensory evaluation was carried out.

RESULTS

The redox potential was temperature dependent. A temperature of 78 °C was chosen to produce the cooked pork sausages with the addition of the spice and herb combinations. The combinations were black mustard, onion, and cumin (at a 1:1:1 ratio); onion, marjoram, and parsley (at a 1:1:1 ratio); black pepper, lemon balm, and parsley (at a 1:2.35:1.65 ratio) and black pepper, cumin, and lovage (at a 1:2:2 ratio). In pork sausages cooked at 78 °C, the variants at 12 g kg^-1 had a more intense aroma and taste than those at 6 g kg^-1 spice and herb combinations, and received a superior sensory evaluation in total.

CONCLUSIONS

The most desirable treatment temperature possibly applied in food products was 78 °C as it gave the highest number of negative results in redox potential of water extracts. The addition of the tested spice and herb combinations contributed to the increase of antioxidant possibility of 78 °C-cooked pork sausages. Further investigation of the redox potential in other meat products (raw meat products at 22 °C, sausages from cooked meat at 100 °C) with the addition of the current spice and herb combinations will be undertaken in subsequent research. © 2020 The Authors. Journal of The Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Comparative Effect of Hammer Mill Screen Size and Cell Wall-Degrading Enzymes During Olive Oil Extraction

The influence of hammer mill screen size (4.5 and 8.5 mm) and enzyme addition (control and 500 ppm) on olive fruit cell wall breakdown and its consequences in terms of oil recovery and the phenolic content of olive oil was studied at the laboratory scale for "Arbequina" and "Koroneiki" at two different maturities. Water recovery and water-soluble carbohydrates in olive paste after malaxation were measured as an indicator of cell wall breakdown. Smaller screen size and enzymes increase oil recovery for Arbequina with a maturity index of 1.6 (6.3-6.6%); and for Koroneiki at a maturity index of 0.2 (15.0-38%) and 2.6 (1.3-4.3%). For both cultivars, the increase in oil recovery is larger in green fruits compared to more ripe fruit. Water recovery and water-soluble carbohydrates increase with small screen size and the enzyme treatments, even when no increment in oil recovery is observed. The water recovery range was 143-239% for Arbequina and 150-262% for Koroneiki; water-soluble carbohydrate range was 1.8-12.7 g/kg for Arbequina and 0.5-5.4 g/kg for Koroneiki. In general, smaller hammer mill screen size and enzymes increase total phenols in the oil, with a larger difference between control and treatment for green fruit than for the ripe fruit. For Arbequina, increases in total phenol content were in the range of 45-60 and 5-20% at maturity index 1.6 and 3.3, respectively. For Koroneiki, the increases were in the range of 31-121 and 7-9% at maturity index 0.2 and 2.6, respectively. Application of cell wall-degrading enzymes improves the cell wall breakdown caused by hammer mill, leading to higher oil recovery and total phenol content. The magnitude of the effect depends on the cultivar and olive fruit maturity.

Aqueous and Enzymatic Extraction of Oil and Protein from Almond Cake: A Comparative Study

The almond cake is a protein- and oil-rich by-product of the mechanical expression of almond oil that has the potential to be used as a source of valuable proteins and lipids for food applications. The objectives of this study were to evaluate the individual and combined effects of solids-to-liquid ratio (SLR), reaction time, and enzyme use on oil and protein extraction yields from almond cake. A central composite rotatable design was employed to maximize the overall extractability and distribution of extracted components among the fractions generated by the aqueous (AEP) and enzyme-assisted aqueous extraction process (EAEP). Simultaneous extraction of oil and protein by the AEP was favored by the use of low SLR (1:12.82) and longer reaction times (2 h), where extraction yields of 48.2% and 70% were achieved, respectively. Increased use of enzyme (0.85%) in the EAEP resulted in higher oil (50%) and protein (75%) extraction yields in a shorter reaction time (1 h), compared with the AEP at the same reaction time (41.6% oil and 70% protein extraction). Overall, extraction conditions that favored oil and protein extraction also favored oil yield in the cream and protein yield in the skim. However, increased oil yield in the skim was observed at conditions where higher oil extraction was achieved. In addition to improving oil and protein extractability, the use of enzyme during the extraction resulted in the production of skim fractions with smaller and more soluble peptides at low pH (5.0), highlighting possible uses of the EAEP skim in food applications involving acidic pH. The implications of the use of enzyme during the extraction regarding the de-emulsification of the EAEP cream warrant further investigation.

Pectinase production by Aspergillus giganteus in solid-state fermentation: optimization, scale-up, biochemical characterization and its application in olive-oil extraction

The application of pectinases in industrial olive-oil processes is restricted by its production cost. Consequently, new fungal strains able to produce higher pectinase titers are required. The aim of this work was to study the capability of Aspergillus giganteus NRRL10 to produce pectinolytic enzymes by SSF and evaluate the application of these in olive-oil extraction. A. giganteus was selected among 12 strains on the basis of high pectinolytic activity and stability. A mixture composed by wheat bran, orange, and lemon peels was selected as the best substrate for enzyme production. Statistical analyses of the experimental design indicated that pH, temperature, and CaCl2 are the main factors that affect the production. Subsequently, different aeration flows were tested in a tray reactor; the highest activity was achieved at 20 L min−1 per kilogram of dry substrate (kgds). Finally, the pectinolytic enzymes from A. giganteus improved the oil yield and rheological characteristics without affecting oil chemical properties.

Approach toward enhancement of halophilic protease production by Halobacterium sp. strain LBU50301 using statistical design response surface methodology

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Halophilic protease producing Halobacterium sp. strain LBU50301 was isolated.

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RSM optimized the fermentation conditions to enhance halophilic protease yield.

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Optimized conditions used in bioreactor resulted about 13-fold enhancement.

A new potent halophilic protease producer, Halobacterium sp. strain LBU50301 was isolated from salt-fermented fish samples (budu) and identified by phenotypic analysis, and 16S rDNA gene sequencing. Thereafter, sequential statistical strategy was used to optimize halophilic protease production from Halobacterium sp. strain LBU50301 by shake-flask fermentation. The classical one-factor-at-a-time (OFAT) approach determined gelatin was the best nitrogen source. Based on Plackett–Burman (PB) experimental design; gelatin, MgSO₄·7H₂O, NaCl and pH significantly influenced the halophilic protease production. Central composite design (CCD) determined the optimum level of medium components. Subsequently, an 8.78-fold increase in corresponding halophilic protease yield (156.22 U/mL) was obtained, compared with that produced in the original medium (17.80 U/mL). Validation experiments proved the adequacy and accuracy of model, and the results showed the predicted value agreed well with the experimental values. An overall 13-fold increase in halophilic protease yield was achieved using a 3 L laboratory fermenter and optimized medium (231.33 U/mL).

Phenolic compounds, antioxidant activity and insulinotropic effect of extracts prepared from grape (Vitis vinifera L) byproducts

Grape byproducts are a rich source of phenolics having immense medicinal properties, but usually wasted from juice/wine processing industries. The present study investigates the phenolic antioxidants and the insulinotropic effect of extracts prepared from seed, skin and stems of two red wine grape cultivars: Pusa Navarang and Merlot. Pusa Navarang cultivar has shown high amounts of total phenolics (95.8 mg/ml), flavonoids (30.5 mg/ml) and flavan-3-ols (21.8 mg/ml) in seed extract and total anthocyanin (4.9 mg/ml) in its skin extract as compared to Merlot cultivar. As determined using HPLC, higher amounts of catechin hydrate (14909 mg/l) and epicatechin (9299 mg/l) were observed in its seed extract, while quercetin hydrate (5849 mg/l) was abundant in its skin extract. Similarly, ferric reducing antioxidant power (FRAP) and ABTS(+). [2,2'-azinobis (3-ethylbenzothiazoline)-6-sulfonic acid] and DPPH. (1,1-diphenyl-2-picrylhy- drazyl) radicals scavenging, were higher in its seed extract, respectively being 134.8 mg/ml of Quercetin equivalent (QE), 18.7 mM of trolox equivalent (TE) and 33.5 mM of TE. Strong correlation was obtained between FRAP and total phenolics, flavonoids and flavan-3-ols contents with correlation coefficients (r(2)) of 0.915, 0.738 and 0.838 respectively. Interestingly, there was a 2-8 fold increase in insulin secretion by isolated mice pancreatic islets at 5.5 mM and 16.5 mM glucose concentration in presence of various extracts. Overall, the seed, skin and stem byproducts of both cultivars are rich sources of phenolics and antioxidants and represent a source of new insulin secretagogues.

Simultaneous extraction of oil and antioxidant compounds from oil palm fruit (Elaeis guineensis) by an aqueous enzymatic process

Oil palm (Elaeis guineensis) fruit was treated with enzymes to facilitate simultaneous recovery of oil and bioactive compounds. Tannase from Paecilomyces variotii, cellulase and pectinase were evaluated for their influence on oil recovery and antioxidant capacity (DPPH), oxidative stability (Rancimat), fatty acid profile, total phenols, total carotenoids and tocols of the oil. Maximum oil recovery (90-93% total oil) was obtained with central composite design using 4% of enzyme preparation (w/w) as 80 U of tannase, 240 U of cellulase and 178 U of pectinase, pH 4, ratio of solution to pulp of 2:1 and 30 min of incubation at 50 °C. Tannase improved the phenolic compounds extraction by 51% and pectinase plus cellulase improved carotene extraction by 153%. Samples treated with tannase showed a 27% and 53% higher antioxidant capacity for the lipophilic and hydrophilic fractions.

Antioxidant activity and biological evaluation of olive pomace extract

The antiradical power of the methanol extracts of olive pomace (Taggiasca cultivar) achieved by high-pressure-high-temperature reactor were investigated using ABTS•(+) and DPPH• assays. The highest antioxidant activity was quantified at 90 min of contact time and 180°C of extraction temperature (64.19 ± 0.16 µg(TE) L(-1) and 15.80 ± 0.62 µg(DPPH) µL(extract) (-1)). The extract with high-antioxidant power resulted to be effective to counteract key aspects of cellular oxidation sensitive mechanisms and inflammation associated to vascular diseases. A linear correlation (p < 0.05) between total polyphenol contents and antioxidant capacity was given by the ABTS•(+) method (R (2) = 0.9184) and DPPH assay (R (2 )= 0.7062).