Application and optimisation of air-steam cooking on selected vegetables: impact on physical and antioxidant properties.

BACKGROUND: Several studies investigated the impact of different cooking techniques on the quality of vegetables. However, the use of the combined air-steam cooking is still scarcely debated, despite the advantages informally referred by professional catering workers. In this study, its optimisation was studied on Brussels sprouts and pumpkin cubes to obtain the best physical (texture, colour) and antioxidant (FRAP, total phenols) response, in comparison to a conventional steaming treatment. RESULTS: Increasing the strength of the air-steam treatment, Brussels sprouts resulted to be softer, less green (higher a* value), richer in phenols and exhibited lower FRAP values than the steamed ones. The air-steamed pumpkin cubes exhibited an equivalent softening degree to that of steamed ones and, under the strongest cooking conditions, a higher antioxidant quality and a yellow darkening (lower b* value). Varying the cooking time and/or temperature, a linear change of force/compression hardness and a* (negative a*: greenness) for Brussels sprouts, b* (yellowness) and total phenol content for pumpkin cubes was observed. A predictive model for these variables was obtained by response surface methodology. The best process conditions to achieve the optimal desirability were also identified. CONCLUSION: The application of air-steam cooking under suitable time/temperature conditions could be proposed as an alternative method to a traditional steam cooking on Brussels sprouts and pumpkin cubes, being able to preserve or improve their quality. The best air-steam cooking conditions were 25 min at 90 °C for Brussels sprouts and 10 min at 110 °C for pumpkin. © 2017 Society of Chemical Industry.

Physical characterization of whole and skim dried milk powders.

The lack of updated knowledge about the physical properties of milk powders aimed us to evaluate selected physical properties (water activity, particle size, density, flowability, solubility and colour) of eleven skim and whole milk powders produced in Europe. These physical properties are crucial both for the management of milk powder during the final steps of the drying process, and for their use as food ingredients. In general, except for the values of water activity, the physical properties of skim and whole milk powders are very different. Particle sizes of the spray-dried skim milk powders, measured as volume and surface mean diameter were significantly lower than that of the whole milk powders, while the roller dried sample showed the largest particle size. For all the samples the size distribution was quite narrow, with a span value less than 2. The loose density of skim milk powders was significantly higher than whole milk powders (541.36 vs 449.75 kg/m3). Flowability, measured by Hausner ratio and Carr's index indicators, ranged from passable to poor when evaluated according to pharmaceutical criteria. The insolubility index of the spray-dried skim and whole milk powders, measured as weight of the sediment (from 0.5 to 34.8 mg), allowed a good discrimination of the samples. Colour analysis underlined the relevant contribution of fat content and particle size, resulted in higher lightness (L*) for skim milk powder than whole milk powder, which, on the other hand, showed higher yellowness (b*) and lower greenness (-a*). In conclusion a detailed knowledge of functional properties of milk powders may allow the dairy to tailor the products to the user and help the food processor to perform a targeted choice according to the intended use.

Crocus cancellatus subsp. damascenus stigmas: chemical profile, and inhibition of α-amylase, α-glucosidase and lipase, key enzymes related to type 2 diabetes and obesity.

Spices are appreciated for their medicinal properties besides their use as food adjuncts to enhance the sensory quality of food. In this study, Crocus cancellatus subsp. damascenus was investigated for its antioxidant activities employing different in vitro systems. Stigma extract demonstrated a radical scavenging activity against both 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) (ABTS) radicals with IC50 values of 34.6 and 21.6 µg/mL and a good ferric reducing ability (53.9 µM Fe(II)/g). In order to clarify the potential functional properties of this spice, the carbohydrate-hydrolysing enzymes and pancreatic lipase inhibitory properties were investigated. Crocus cancellatus subsp. damascenus extract inhibited α-amylase and α-glucosidase with IC50 values of 57.1 and 68.6 µg/mL, respectively. The bioactivity was discussed in terms of phytochemicals content. The obtained results may be of interest from a functional point of view or as food additive and to promote the revalorization of this species.

Chemical Profile and Antioxidant Properties of Extracts and Essential Oils from Citrus × limon (L.) Burm. cv. Femminello Comune.

Citrus × limon cv. Femminello Comune (Rutaceae) from Rocca Imperiale (Italy), one of the six Protected Geographical Indication (PGI) Italian lemon crops, has been recently received renewed interest. In this work, fresh and dried peels and leaves were extracted by hydrodistillation, supercritical fluid extraction (SFE), and Soxhlet apparatus. Chemical profile was assessed by gas chromatography (GC) and gas chromatography/mass spectrometry (GC/MS). Except for leaves extracts obtained by Soxhlet apparatus, the monoterpene hydrocarbons fraction dominated. Limonene, γ-terpinene, and ß-pinene were the main identified compounds. The antioxidant activity was investigated using different in vitro assays namely 2,2-diphenyl-1-picrylhydrazyl (DPPH), ABTS, ferric reducing ability power (FRAP), and ß-carotene bleaching test. In DPPH test, the essential oil obtained by hydrodistillation of fresh peel exhibited the highest activity (IC50 of 1.17 mg/ml). Leaves extracted by SFE showed a good activity in both DPPH and ß-carotene bleaching test with IC50 values of 2.20 and 6.66 mg/ml, respectively. Monoterpene hydrocarbons fraction exhibited a positive Pearson's correlation coefficient with all antioxidant assays. Leaves, often considered waste material, should be considered from a different point because they represent a matrix of indisputable interest.

Effect of different cooking methods on structure and quality of industrially frozen carrots.

The effect of boiling, steaming and microwaving on microstructure, texture and colour of raw and industrially frozen carrots was investigated. The raw carrots, after cooking, showed dehydrated and separated cells with swollen walls. The carrots subjected to blanching, freezing and followed by frozen storage exhibited marked tissue damages indicating deep oriented fissures. Cooking caused cellular dehydration and separation in the tissue, with the same intensity between raw and frozen carrots and independently from the cooking treatment applied. Among different cooking methods, microwaving showed better retention of the initial texture and colour quality for both raw and frozen carrots. On the other hand, the steamed carrots revealed the highest degree of softening and colour differences from the control for both raw and frozen carrots, despite the worst tissue conditions were observed for the boiled carrots.

In vitro investigation of the bioaccessibility of carotenoids from raw, frozen and boiled red chili peppers (Capsicum annuum).

BACKGROUND: Carotenoid-rich foods are associated with antioxidant activity and the ability to alleviate chronic diseases. PURPOSE: The present study investigated the effect of processing on the content and bioaccessibility of carotenoids from 13 cultivars of red chili pepper (Capsicum annuum). METHODS: Carotenoids in chili peppers were analyzed before an in vitro digestion process. The portion of carotenoid transferred to the micelle fraction (bioaccessibility) was also quantified. RESULTS: ß-Carotene, ß-cryptoxanthin, capsanthin and antheraxanthin were the most abundant carotenoids. Zeaxanthin, violaxanthin, neoxanthin and lutein were detected at lower concentrations. In general, freezing and boiling reduced carotenoid contents. Capsanthin and zeaxanthin had the highest bioaccessibility at an average value from 36 to 40%, followed by antheraxanthin (26%). Bioaccessibility of ß-cryptoxanthin, violaxanthin and ß-carotene was lower, averaging 6.1, 4.8 and 4.0%, respectively. Neoxanthin and lutein were not detected in micelles. Freezing increased the bioaccessibility of capsanthin, zeaxanthin, antheraxanthin, ß-cryptoxanthin and violaxanthin; ß-cryptoxanthin bioaccessibility increased and capsanthin and zeaxanthin bioaccessibility decreased following boiling. CONCLUSIONS: Differences in the contents and bioaccessibility of carotenoids in 13 C. annuum cultivars and between the processed methods were herein evidenced.

Chemical profiling and in vitro biological effects of Cardiospermum halicacabum L. (Sapindaceae) aerial parts and seeds for applications in neurodegenerative disorders.

Cardiospermum halicacabum is widely used in traditional medicine. Previous studies have focused on the aerial parts, while the seeds have been poorly investigated. This work aimed to analyse the chemical composition of extracts from aerial parts and seeds obtained using Naviglio and Soxhlet (PN, PS, and SN, SS, respectively), the inhibitory properties against tyrosinase, acetylcholinesterase (AChE), and butyrylcholinesterase (BChE) and the antioxidant effects. PN total extract showed significant anti-tyrosinase activity (IC50 value of 10.8 µg/mL). After partitioning with n-hexane, an HPLC method for analysing chemical constituents was established. Apigenin, luteolin, and apigenin-7-O-glucoside are the predominant constituents. SN n-hexane fraction was the most active inhibitor of BChE (IC50 of 57.9 µg/mL). Gas chromatography-mass spectrometry analysis revealed fatty acids, including eicosanoic acid, methyl 11-eicosenoate and oleic acid, as the major constituents. These findings suggest the potentiality of both seeds and aerial parts of C. halicacabum in the treatment of neurological disorders.

Chemical composition and bioactivity of dried fruits and honey of Ficus carica cultivars Dottato, San Francesco and Citrullara.

BACKGROUND: The aim of this study is to evaluate, for the first time, the chemical profile, antioxidant properties and cholinesterase inhibitory activity of dried fruits and honey of Ficus carica (fig) cultivars Dottato, Citrullara, and San Francesco. RESULTS: Gas chromatography-mass spectrometry (GC-MS) analysis of fig extracts identified terpenes, sterols and fatty acids as major constituents. The aroma profile of honey obtained from a mixture of the three cultivars was investigated by solid-phase micro-extraction/GC-MS. 5-(Hydroxymethyl)-2-furancarboxaldehyde, 2,3-dihydro-3,5-dihydroxy-6-methyl-4H-pyran-4-one and 1,3-dihydroxy-2-propanone were the main compounds. Total phenol, flavonoid and anthocyanin content are also reported. The San Francesco cultivar is characterised by the highest phenol and flavonoid content, while Dottato showed the major anthocyanin content. The Dottato cultivar exhibited the best radical scavenging activity against both 2,2'-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid) and 2,2-diphenyl-1-picrylhydrazyl radicals (IC50 values of 5.4 and 22.6 µg mL(-1) , respectively). This cultivar also showed the highest inhibitory activity against both acetylcholinesterase and butyrylcholinesterase, with IC50 values of 26.9 and 31.8 µg mL(-1) , respectively. CONCLUSION: Dried figs are a convenient source of bioactive compounds that demonstrated potential neuroprotection and antioxidant effects. Therefore, the addition of figs to the human diet should be recommended by dieticians and nutritionists.

In vitro assessment of the bioaccessibility of carotenoids from sun-dried chilli peppers.

Chilli peppers have been recognized as an excellent source of antioxidants as they are rich in bioactive phytochemicals such as carotenoids which are known to exert various beneficial effects in vivo. Absorption is an important factor in the determination of the potential biological effects of carotenoids. The bioaccessibility of a food constituent such as a carotenoid represents its potential to be absorbed in humans. There is very limited information in the literature regarding the content and bioaccessibility of carotenoids from dried peppers. Therefore, the objectives of the present study were: first, to determine the carotenoid content of 20 varieties of red, orange or yellow coloured sun-dried chilli peppers belonging to either of four Capsicum species (annuum, baccatum, chinense and chacoense); and second, to quantify the carotenoid micellarization (bioaccessibility) following an in vitro digestion procedure. Red peppers had a higher carotenoid content and bioaccessibility than either the orange peppers or yellow pepper. Xanthophylls showed greater bioaccessibility than carotenes. Our findings confirm that dried chilli peppers are a good source of carotenoids.

Chelating, antioxidant and hypoglycaemic potential of Muscari comosum (L.) Mill. bulb extracts.

The metal chelating activity, antioxidant properties and the effect on carbohydrate-hydrolysing enzyme inhibition of Muscari comosum extracts have been investigated. M. comosum bulbs contain a total amount of the phenols with a value of 56.6 mg chlorogenic acid equivalent per gram of extract and a flavonoid content of 23.4 mg quercetin equivalent per gram of extract. In order to evaluate the non-polar constituents, n-hexane extract was obtained. Gas chromatography-mass spectrometry analysis revealed the presence of fatty acids and ethyl esters as major constituents, with different aldehydes and alkanes as minor components. Ethanolic extract had the highest ferric-reducing ability power (66.7 µM Fe(II)/g) and DPPH scavenging activity with a concentration giving 50% inhibition (IC50) value of 40.9 µg/ml. Moreover, this extract exhibited a good hypoglycaemic activity with IC50 values of 81.3 and 112.8 µg/ml for α-amylase and α-glucosidase, respectively. In conclusion, M. comosum bulbs show promising antioxidant and hypoglycaemic activity via the inhibition of carbohydrate digestive enzymes. These activities may be of interest from a functional point of view and for the revalorization of this ancient non-cultivated vegetable of Mediterranean traditional gastronomy.

Improved Physicochemical and Structural Properties of Blueberries by High Hydrostatic Pressure Processing.

The use of high pressure on fruits and vegetables is today widely studied as an alternative to the traditional thermal preservation techniques, with the aim of better preserving nutritional and organoleptic properties. The use of high hydrostatic pressures (400-600 MPa; 1-5 min; room temperature) was tested on the physicochemical and structural properties of blueberries, in comparison to raw and blanched samples. High hydrostatic pressures led to higher tissue damages than blanching, related to the intensity of the treatment. The cellular damages resulted in leakage of intracellular components, such as bioactive molecules and enzymes. As a consequence, among the high pressure treatments, the resulting antioxidant activity was higher for samples treated for longer times (5 min). Pectinmethyl esterase (PME), deactivated by blanching, but strongly barotolerant, was more active in blueberries treated with the more intense high pressure conditions. Blueberry texture was better retained after high pressure than blanching, probably because of the PME effect. Blueberry color shifted towards purple tones after all of the treatments, which was more affected by blanching. Principal component analysis revealed the mild impact of high pressure treatments on the organoleptic properties of blueberries.

Insights into the Analysis of Phenolic Secoiridoids in Extra Virgin Olive Oil.

Extra virgin olive oils (EVOOs) containing more than 5 mg/20 g tyrosol, hydroxytyrosol, and their secoiridoids can be recognized by health claims related to the protection of blood lipids from oxidative stress. Therefore, a reliable, accurate, and standardized analytical procedure is needed to determine these markers of EVOO quality. In order to overcome the limitations of current methods, a detailed investigation of sample preparation and chromatographic conditions was performed by UHPLC-UV-HRMS. The use of a C18 fused-core column and nonacidified gradient elution provided single, sharp peaks for oleocanthal and oleacein, allowing their reliable quantitation in UV profiles. Positive- and negative-UHPLC-HRMS/MS characterization of methanolic extracts revealed the presence of dimethyl acetal, methyl hemiacetal, and monohydrate derivatives of all secoiridoids. These artifacts were formed in aqueous methanol, which is usually employed to extract and analyze EVOO phenols, making the HPLC profiles more complex and the measurements less accurate and reproducible. Acetonitrile proved to be a suitable solvent to avoid the formation of secoiridoid dimethyl acetals and methyl hemiacetals and to efficiently extract EVOO bioactive phenols. Finally, the phenolic contents of Italian EVOO samples were determined by UHPLC-UV analysis of acetonitrile extracts before (direct method) and after acid hydrolysis (indirect method). The results indicated that the use of tyrosol and hydroxytyrosol as reference standards allowed more accurate quantitative data to be obtained. Direct and indirect methods provided comparable levels of EVOO phenols, highlighting the usefulness of acid hydrolysis in routine analyses. The improved procedure defines the most reliable conditions to provide an analytical method with suitable accuracy and repeatability in the analysis of healthy and functional EVOO phenols.

Edible Flowers: A Rich Source of Phytochemicals with Antioxidant and Hypoglycemic Properties.

Edible flowers are receiving renewed interest as rich sources of bioactive compounds. Ethanol extracts of eight edible flowers were phytochemically characterized and investigated for their bioactivity. Rutin, quercetin, luteolin, kaempferol, and myricetin were selected as standards and quantified by HPLC. The fatty acid profile was analyzed by GC and GC-MS. Antioxidant properties were evaluated by using different in vitro tests. The hypoglycemic effects were investigated via the inhibition of α-amylase and α-glucosidase. Sambucus nigra exhibited the highest radical-scavenging activity (IC50 of 1.4 µg/mL), followed by Hedysarum coronarium (IC50 of 1.6 µg/mL). Both species contained high quercetin and rutin contents. S. nigra extract exerted the highest activity in preventing lipid oxidation. Malva sylvestris extract inhibited both α-amylase and α-glucosidase with IC50 values of 7.8 and 11.3 µg/mL, respectively. These findings support the consumption of edible flowers as functional foods and their use as sources of natural antioxidants by the food industry.

Effect of bioclimatic area on the composition and bioactivity of Tunisian Rosmarinus officinalis essential oils.

The chemical composition of eight Tunisian Rosmarinus officinalis L. populations (A-H) from different bioclimatic areas has been examined by gas chromatography (GC) and GC-mass spectrometry. The essential oils are characterised by high amounts of oxygenated monoterpenes (58.2-71.7%) followed by monoterpene hydrocabons (15.1-26.7%). 1,8-Cineole, camphor, α-pinene and borneol are the main representative components. The antioxidant activity was investigated by 2,2-diphenyl-1-picrylhydrazyl radical (DPPH), ferric reducing ability power assay and ß-carotene bleaching test. Samples showed antiradical activity by inhibiting DPPH radical with IC50 values ranging from 375.3 to 592.8 µg mL(- 1) for samples F and A, respectively. Sample A also showed the most promising activity in ß-carotene bleaching test (IC50 of 31.9 µg mL(- 1)). The essential oils were also screened for acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) inhibitory activity. Sample G showed the highest activity against AChE (IC50 of 64.7 µg mL(- 1)) while sample D (IC50 of 29.5 µg mL(- 1)) exhibited the most potent activity against BChE.

Influence of drying and cooking process on the phytochemical content, antioxidant and hypoglycaemic properties of two bell Capsicum annum L. cultivars.

The present study evaluates the influence of drying and cooking processes on the health properties of two bell Capsicum annuum L. cultivars Roggiano and Senise compared with fresh peppers. The content of phytochemicals decreased in the order fresh>dried>dried frying processes. HPLC analysis was applied to quantify five flavonoids from peppers. Apigenin was identified as main constituent. Its content was affected by drying and dried frying processes. The antioxidant activity was evaluated by DPPH, ABTS, ß-carotene bleaching test and Fe-chelating activity assay. A comparable radical scavenging activity was observed for both cultivars. Interestingly, frying process did not influenced this property. Roggiano peppers exhibited the highest antioxidant activity using ß-carotene bleaching test with IC(50) values of 38.1 and 24.9 µg/mL for total extract and n-hexane fraction, respectively. GC-MS analysis of lipophilic fraction revealed the presence of fatty acids and vitamin E as major components. In the inhibition of the carbohydrate-hydrolyzing enzymes fresh Senise peppers exerted the strongest activity against α-amylase with an IC(50) value of 55.3 µg/mL. Our results indicate that C. annuum cultivars Roggiano and Senise have an interestingly potential health benefits not influenced by processes that are used before consumption.

Phenolics, aroma profile, and in vitro antioxidant activity of Italian dessert passito wine from Saracena (Italy).

A traditional sweet dessert wine from Saracena (Italy), made with nonmacerated local white grapes (Guarnaccia, Malvasia and Moscato), was analyzed for phenolics and aroma profile and antioxidant activities. The most abundant classes of phenols identified by high-performance liquid chromatography were hydroxybenzoic acids and flavan-3-ols, where gallic acid showed the highest content (376.5 mg/L). The analysis by solid phase microextraction-gas chromatography-mass spectrometry revealed the presence of superior alcohols (from iso-butanol and iso-amyl alcohol up to 2-phenylethanol) and their ethyl esters, terpenes (such as linalool), furfuryl compounds, and free fatty acids (up to palmitic acid) as the key odorants of this wine. The antioxidant activity, evaluated by different in vitro assays 2,2-diphenyl-1-picrylhydrazyl (DPPH), 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid (ABTS), and ß-carotene bleaching test), showed that passito wine had a radical scavenging activity (IC50 value of 0.03 v/v against DPPH·) and inhibited linoleic acid oxidation with an IC50 value of 0.4 v/v after 30 min of incubation.

The effect of domestic processing on the content and bioaccessibility of carotenoids from chili peppers (Capsicum species).

The content and bioaccessibility of carotenoids from different chili peppers were analysed and the effects of typical domestic processing were investigated. Peppers were analysed before and after cooking by conventional boiling (10 min in 100 °C water) and also following a freezing period of four months in a domestic freezer (-20 °C). The content and bioaccessibility of the eight carotenoids quantified varied, depending on cultivar, species, colour and processing. Provitamin A carotenoids (ß-carotene and ß-cryptoxanthin) and capsanthin were present at highest concentrations in the samples before and after processing. In general, yellow and orange peppers were the best sources of lutein, zeaxanthin and neoxanthin. Xanthophyll carotenoids were more efficiently transferred to the micelles and, therefore, were also more bioavailable. Processing decreased the carotenoid content in certain samples; however, the micellar content was generally not lower for processed peppers; therefore the bioaccessibility of carotenoids from processed peppers is enhanced relative to unprocessed peppers.