Quantitative Determination of Biogenic Element Contents and Phytochemicals of Broccoli (Brassica oleracea var. italica) Cooked Using Different Techniques.

In this study, the effect of different cooking techniques on broccoli moisture, total phenolic, total flavonoid, and radical scavenging capacity results, polyphenol contents, and their quantitative values was investigated. The total phenolic quantities of fresh and cooked broccoli samples were assessed to be between 36.32 (conventional boiling) and 423.39 mg GAE/100 g (microwave heating). The radical scavenging activities of the broccoli samples were reported between 2.55 (conventional boiling) and 4.99 mmol/kg (microwave heating). In addition, catechin and rutin quantities of the fresh and cooked broccoli samples were measured to be between 2.24 (conventional boiling) and 54.48 mg/100 g (microwave heating), and between 0.55 (conventional boiling) and 16.33 mg/100 g (microwave heating), respectively. The most abundant elements in fresh and cooked broccoli samples were K, Ca, P, S, and Mg. The results showed some changes depending on cooking techniques compared to the control. The bioactive properties of broccoli samples cooked by means of conventional boiling, boiling in vacuum bag, and high-pressure boiling were established to be lower compared to the fresh sample. Catechin, 3,4-dihydroxybenzoic acid, rutin, and gallic acid were the key phenolic compounds of fresh and cooked broccoli samples. The phenolic components of broccoli were significantly affected by the applied cooking techniques. The highest protein in broccoli samples was determined in the broccoli sample cooked by boiling in a vacuum bag. There were statistically significant changes among the mineral results of broccoli cooked with different cooking methods.

Effect of roasting times on bioactive compounds, fatty acids, polyphenol and nutrients of amaranth (Amaranthus cruentus L.) seed roasted in pan, and principal component analysis.

In this study, the effect of roasting times on bioactive compounds, antioxidant capacity, fatty acids, polyphenol and nutrients of amaranth seed and oils roasted in pan at 120 °C was investigated. Total phenolic and flavonoid results of the seeds of unroasted (control) and roasted-amaranth were recorded between 48.81 (6 min) and 231.35 mg GAE/100 g (15 min) to 64.29 (6 min) and 144.29 mg/100 g (15 min), respectively. Antioxidant activities of unroasted and roasted-amaranth extracts were recorded between 5.50 (control) and 12.78 mmol/kg (15 min). L* values of amaranth seeds ranged from 51.21 to 78.53. Roasting for 3 min and 6 min was increased the L* values of samples, while roasting for 9-12 min caused a decrease in L* values. Gallic acid results of amaranth seeds were identified between 21.94 (control) and 71.06 mg/100 g (15 min). The linoleic acid results of amaranth seed oils were reported between 44.24 (control) and 45.76% (12 min). The highest amounts of elements in roasted and unroasted amaranth seeds were P, K,Ca, Mg and S. In general, it was observed that both macro and micro-elements of amaranth seed samples increased with the application of heat treatment. However, microelement contents differed depending on the roasting time. Graphical abstract: In this study, the effect of thermal process times on total phenol, flavonoid, antioxidant activity, fatty acids, phenolic and minerals of amaranth seed and oils roasted in pan at 120 °C was investigated.

Influence of microwave heating on bioactive properties, phenolic compounds and fatty acid profiles of pomegranate seed oil.

In this study, the effects of different microwave powers on the bioactive properties, fatty acid and phenolic profiles of pomegranate seed oil were reported using various analytical methods, GC and HPLC. Antioxidant capacity and total phenolic values of pomegranate seed oils were established between 14.16% (control) and 19.18% (720 and 900 W) to 0.00 (900 W) and 3.61 mgGAE/100 g (control), respectively. The viscosity values of pomegranate seed oil increased with the heat treatment. But, the viscosity of the oils increased with the applied Watt increase. The p-coumaric acid amounts of the seed oils heated at 180, 720 and 900 W in the microwave were found to be statistically similar. In general, phenolic compounds of pomegranate seed oils did not show a constant increase or decrease depending on microwave power. The key fatty acid of pomegranate seed oil was punisic acid (30.49-36.10%). followed by linoleic acid (25.95-30.01%).

Changes in antioxidant activity, phenolic compounds, fatty acids, and mineral contents of raw, germinated, and boiled lentil seeds.

Lipid contents of lentil seeds were determined between 1.02% (germinated) and 1.23% (boiled). Total phenolic and flavonoid amounts of processed lentils were detected between 45.32 mgGAE/100 g (germinated) and 68.02 mgGAE/100 g (control) to 70.95 mgQE/100 g (germinated) and 199.52 mgQE/100 g (control), respectively. Also, antioxidant activity values of lentil seeds were detected between 0.70 mgTE/kg (germinated) and 3.35 mgTE/kg (boiled). The major phenolic compounds of raw, germinated, and boiled lentil seeds were gallic acid, 3,4-dihydroxybenzoic acid, and catechin. While oleic acid amounts of lentil oils vary between 33.22% (control) and 47.72% (germinated), linoleic acid amounts of lentil oils were detected between 26.40% (germinated) and 40.91% (boiled). In addition, linolenic acid amounts of lentil oils were determined between 4.12% (germinated) and 6.97% (boiled).The key minerals of raw, germinated, and boiled lentil seeds were P, K, Mg, and S. However, according to the results, it was determined that lentils are a good source of potassium. PRACTICAL APPLICATION: Lentil is one of the oldest known food products used only in human food. Lentils are an excellent source of phytochemical nutrients. Lentils are widely used in salads, casseroles, and soups as well as in vegetarian cuisine. Lentil is considered a good source of energy along with high fiber content. Germination plays an important role in reducing nonnutritive compounds in legumes.

Investigation of the Potential Use, Phytochemical and Element Contents of Acacia Plant Seeds Grown in Wild Form, Considered as Environmental Waste.

In this study, the effect of altitude on oil amounts, antioxidant activity, polyphenol content and mineral contents of Acacia seeds collected from two different locations (up to 1100 m above sea level) was investigated. Total carotenoid and flavonoid contents of Acacia seeds were detected as 0.76 (Konya) and 1.06 µg/g (Tasucu-Mersin) to 1343.60 (Konya) and 184.53 mg/100 g (Tasucu-Mersin), respectively. Total phenol contents and antioxidant activity values of Acacia seeds were identified as 255.11 (Konya) and 190.00 mgGAE/Tasucu-Mersin) to 64.18% (Konya) and 75.21% (Tasucu-Mersin), respectively. The oils extracted from Acacia seeds in Konya and Mersin province contained 62.70% and 70.39% linoleic, 23.41% and 16.03% oleic, 6.45%and 6.04% palmitic and 2.93% and 4.94% stearic acids, respectively. While 3,4-dihydroxybenzoic acid amounts of seeds are determined as 3.89 (Konya) and 4.83 mg/100 g (Tasucu-Mersin), (+)-catechin contents of Acacia seeds were identified as 3.42 (Konya) and 9.51 mg/100 g (Tasucu-Mersin). Also, rutintrihydrate and ferulic contents of Acacia seeds were found as 23.37 (Konya) and 11.87 mg/100 g (Tasucu-Mersin) to 14.74 mg/100 g (Konya) and 1.12 mg/100 g (Tasucu-Mersin), respectively. Acacia seeds collected from Konya and Mersin contained 4003.75 and 3540.89 mg/kg P, 9819.12 and 16175.69 mg/kg K, 4347.47 and 5078.81 mg/kg P, 2195.77 and 2317.90 mg/kg Mg, 1015.75 and 2665.60 mg/kg S and 187.53 and 905.52 mg/kg Na, respectively.

The Effect of Plant Essential Oil and Extracts on Fatty Acid Profile of Virgin Olive Oil Stored in Different Packaging Materials.

In this study, the combined effect of different packaging materials (transparent PET, transparent glass, glass-PET bottle and tin), some aromatic herbs (thyme, rosemary, sage and olive leaf) and also their essential oils (thyme, rosemary and sage) on fatty acid composition of virgin olive oil was investigated during storage period. The initial amounts of the main fatty acids as oleic, palmitic and linoleic acids were determined as 72.89%, 11.89% and 8.96%, respectively. The addition of aromatic plants and essential oils did not effect the fatty acid profile. Also, packaging materials had a minor influence on fatty acids. In the 6th month of storage, the oleic acid contents of olive oils showed the increase in all of samples. The highest increase was observed in olive oil stored in glass-PET (74.30-75.01%), followed by stored in glass bottle (73.41-74.82%). Generally, during the storage, the differences of fatty acid contents were in minor level. The fatty acid composition of olive oils stored under different essential oil and extract concentrations showed partial differences depending on the extract type and concentration.

Effect of different roasting methods on the bioactive properties, phenolic compounds and fatty acid compositions of pomegranate (Punica granatum L. cv. Hicaz) seed and oils.

In this study, whole and ground pomegranate (cv. Hicaz) seeds using conventional and microwave ovens were investigated under different parameter. The results show that the total phenolic contents of whole and ground seeds roasted in oven at (150 °C) and microwave at (720 W) for 10 and 20 min, and 5 and 7.5 min, respectively, were found to be slightly higher than those of the control group. In addition, the same roasting method of microwave at (720 W), ground seed oils showed greater fatty acids contents than those of whole seed oils. According to achieved results, roasting techniques used caused noticeable fluctuations of phenolic and fatty acids contents and that depending on which counterparts of pomegranate seeds treated. In addition, a caution recommended when using microwave oven in roasting pomegranate seeds to prevent undesirable alteration or losing of bioactive properties of this value-added product.

Phenolic Compounds, Antioxidant Activity and Fatty Acid Composition of Roasted Alyanak Apricot Kernel.

The oil recovery from Alyanak apricot kernel was 36.65% in control (unroasted) and increased to 43.77% in microwave-roasted kernels. The total phenolic contents in extracts from apricot kernel were between 0.06 (oven-roasted) and 0.20 mg GAE/100 g (microwave-roasted) while the antioxidant activity varied between 2.55 (oven-roasted) and 19.34% (microwave-roasted). Gallic acid, 3,4-dihydroxybenzoic acid, (+)-catechin and 1,2-dihydroxybenzene were detected as the key phenolic constituents in apricot kernels. Gallic acid contents varied between 0.53 (control) and 1.10 mg/100 g (microwave-roasted) and 3,4-dihydroxybenzoic acid contents were between 0.10 (control) and 0.35 mg/100 g (microwave-roasted). Among apricot oil fatty acids, palmitic acid contents ranged from 4.38 (oven-roasted) to 4.76% (microwave-roasted); oleic acid contents were between 65.73% (oven-roasted) and 66.15% (control) and linoleic acid contents varied between 26.55 (control) and 27.12% (oven-roasted).

Effect of Maturing Stages on Bioactive Properties, Fatty Acid Compositions, and Phenolic Compounds of Peanut (Arachis hypogaea L.) Kernels Harvested at Different Harvest Times.

The present study investigated the effects of harvesting time on the physicochemical properties, antioxidant activity, fatty acid composition, and phenolic compounds of peanut kernels. The moisture content (air-dried basis) of peanut kernels was determined between 4.47% (September 15, 2019) and 7.93% (October 6, 2019), whereas the oil contents changed from 45.95% (October 6, 2019) to 49.25% (September 22, 2019). The total carotenoid, chlorophyll, and phenolic contents were low throughout the harvest, showing differences depending on the harvest time. Total phenolic content changed from 0.28 mg GAE/L (September 29, 2019) to 0.43 mg GAE/L (September 8, 2019), whereas the antioxidant activity varied from 4.42% (August 25, 2019) to 4.70% (September 1, 2019). The dominant fatty acids were palmitic, oleic, and linoleic acids, depending on the harvest time, followed by stearic, behenic, arachidic, and linolenic acids. The (+)-catechin content ranged from 2.17 mg/L (September 8, 2019) to 5.15 mg/L (September 1, 2019), whereas 1,2-dihydroxybenzene content changed between 2.67 mg/L (October 6, 2019) and 5.85 mg/L (September 29, 2019). The phenolic compound content fluctuated depending on the harvest time. The results showed that peanut kernel and oil had distinctive phenolic profiles and fatty acid contents. The findings of the present study may provide information for the best time to harvest peanut to achieve its maximum health benefits.

Influence of Drying Methods on Bioactive Properties,Fatty Acids and Phenolic Compounds of Different Parts of Ripe and Unripe Avocado Fruits.

All drying processes increased oil content, antioxidant activity, total phenolic contents, and most of the phenolic compounds in the pulp, peel and seeds of both ripe fruits with varied degrees (p < 0.05). In addition, the processes reduced the oil contents, linoleic acids, 3,4-dihydroxybenzoic acid, (+)-catechin, and naringenin of the pulp, antioxidant activity of the peels and seeds, and 3,4-dihydroxybenzoic acid, (+)-catechin of the seeds and it enhanced all other parameters in the pulp, peel, and seeds of unripe fruits (p < 0.05). Comparing the phenolic profiles of avocado pulp, peels, and seeds of ripe and unripe fruits indicated that the peel and seeds are richer than the pulp and that is superior in unripe fruits than ripe ones. In addition, drying processes particularly microwave and air drying greatly enhanced the bioactive properties of ripe and unripe avocado fruits and could thus be used to elongate the shelf-life of avocado fruit products without major impact on the overall quality.

Influence of drying techniques on bioactive properties, phenolic compounds and fatty acid compositions of dried lemon and orange peel powders.

Lemon peel powder (LPP) obtained after drying (microwave, infrared, and oven) showed the lowest (58.72%) DPPH-radical scavenging activity in oven-dried and the highest (67.84%) in infrared-dried LPP while that of fresh lemon peel remained 63.22%. Orange peel powder (OPP) showed the lowest DSA (61.65) after microwave and the lowest (63.54%) after infrared-drying while that of fresh orange peel was 63.48%. Total phenolics were between 114.58 (fresh) and 179.69 mgGAE/100 g (oven) in LPP and between 158.54 (fresh) and 177.92 mgGAE/100 g (infrared) in OPP. The total flavonoid contents were 380.44 (fresh)-1043.04 mg/100 g (oven) in case of LPP and 296.38 (fresh)-850.54 mg/100 g (oven) in case of OPP. The gallic acid contents were 2.39 (fresh)-14.02 mg/100 g (oven) in LPP. The (+)-catechin contents were 1.10 (fresh)-49.57 mg/100 g (oven) for LPP and 0.82 (fresh)-7.63 mg/100 g (infrared) in case of OPP. The oleic acid content was 22.99 (infrared)-58.85% (fresh) in LPP-oil and 28.59 (microwave)-61.65% (fresh) in OPP-oil. The linoleic acid contents were 13.76 (fresh)-36.90% (oven) in LPP-oil and 14.14 (fresh)-37.08% (infrared) in case of OPP-oil. The drying techniques showed profound but variable effects on radical scavenging activity, total phenolics, flavonoid, carotenoids, phenolic compounds and fatty acid composition of both LPP and OPP and oven-drying (60 °C) was the most effective in improving these bioactive constituents.

Tocopherol Contents of Pulp Oils Extracted from Ripe and Unripe Avocado Fruits Dried by Different Drying Systems.

The tocopherol contents of unripe and ripe avocado fruit oil extracted from Pinkerton, Hass and Fuerte varieties were determined after drying fruit using air, microwave or oven drying methods. The α-tocopherol content changed between 13.70 mg/100 g (microwave-dried) and 28.06 mg/100 g (air-dried) in oil from unripe Pinkerton fruit; between 14.86 mg/100 g (microwave-dried) and 88.12 mg/100 g (fresh) in oil from unripe Hass fruit and between 13.31 mg/100 g (microwave-dried) and 17.35 mg/100 g (oven-dried) in oil from unripe Fuerte fruit. The α-tocopherol contents in oil from ripe Fuerte fruit changed between 13.21 mg/100 g (fresh) and 17.61 mg/100 g (oven-dried). In addition, γ-tocopherol contents varied between 11.55 mg/100 g (air-dried) and 14.61 mg/100 g (microwave-dried) unripe "Pinkerton" fruit; between 11.52 mg/100 g (air-dried) and 15.01 mg/100 g (fresh) in unripe Hass fruit and between 12.17 mg/100 g (air-dried) and 15.27 mg/100 g (microwave-dried) unripe Fuerte fruit. The γ-tocopherol contents ranged from 12.71 mg/100 g (fresh) to 17.40 mg/100 g (oven-dried) in ripe Hass fruit; from 10.29 mg/100 g (fresh) and 17.20 mg/100 g (microwave-dried) ripe Fuerte fruit. α-, ß-, γ- and δ-tocopherols could not be detected in ripe fresh Pinkerton fruit. In general, ß- and δ-tocopherol could not be detected in most of the unripe and ripe avocado fruit oils. α-Tocopherol and γ-tocopherol contents of dried ripe Fuerte fruit oils were found to be higher compared to those of dried unripe Fuerte fruits.

Effect of conventional oven roasting treatment on the physicochemical quality attributes of sesame seeds obtained from different locations.

The impacts of conventional oven roasting at different temperatures and for different times on the physicochemical attributes of sesame seeds obtained from different regions was assessed. The color characteristics (a*, b*, and L* values), ash, moisture, protein, oil, total phenolic, and antioxidant activity of raw sesame seeds and the peroxide value, p-anisidine, fatty acids, and tocopherols of sesame oil varied with source. Oven roasting temperature and time significantly affected the physicochemical properties and bioactive components of sesame seeds and the oil quality from different countries. Roasting variably increased the a* value, antioxidant activity, protein, oil, total phenolic, and tocopherol content, and p-anisidine and peroxide values, whereas it reduced b* and L* values, moisture, and linolenic acid content of sesame seeds from different countries. Roasting conditions and growing locations affected the physiochemical composition and bioactive compounds of seeds. Such factors can influence the quality attributes of sesame seeds and oil and should be considered during processing.

Effect of Frying on Physicochemical and Sensory Properties of Potato Chips Fried in Palm Oil Supplemented with Thyme and Rosemary Extracts.

Quality parameters of potato chips (flat and serrated) fried either in palm oil (PO) alone or containing natural (thyme (TPO) and rosemary (RPO) extracts) and synthetic BHT (BPO) antioxidants were evaluated during storage period. The free fatty acid and peroxide values of chips fried in PO (control) were found between 0.18 and 0.21% to 1.00 and 1.04 meqO2/kg during the first storage month, respectively. However, these values were 0.07-0.10% and 0.55-0.90 meqO2/kg for chips fried in TPO, respectively. The water contents increased when storage time increased from 1 to 7 month and their values changed between 0.49 and 1.95% (flat potato chips in BPO) and between 0.88 and 1.24% (serrated potato chips in TPO). The total trans-fat contents were 0.13% (serrated potato chips in BPO) and 0.35% (both flat and serrated potato chips in PO) at the start of storage. The total trans-fat content after 7 months were 0.13% (PO fried flat and serrated potato chips) and 0.17% (serrated potato chips fried in BPO, TPO and RPO). The acrylamide contents varied between 152 (serrated potato chips in PO) and 540 µg/kg (flat potato chips fried in RPO) at the beginning of storage. However, the acrylamide contents changed during 7th storage month and ranged from 182 (serrated potato chips in PO) to 518 µg/kg (flat potato chips in RPO). Among fatty acids, while palmitic acid are determined between 37.14 (flat chips in PO) and 41.60% (serrated chips in TPO), oleic acid varied between 30.0 (flat chips in RPO) and 33.00% (serrated chips in PO). Sensory evaluation showed that PO containing antioxidants showed better consumer preference for potato chips until the end of storage.

Effect of Microwave Treatment on Oil Contents, Fatty Acid Compositions and Mineral Contents of Hazelnut Varieties.

The oil content of both 'raw' and hazelnut kernels was significantly (p < 0.05) reduced as the microwave power increased from 180 W to 360 W. The contents of fatty acids flucuated for all varieties with microwave power, with a significant (p < 0.05) increment observed for 'Sivri' hazelnut at 180 and 720 W. The maximum linoleic acid contents for 'Raw', 'Sivri' and 'Tombul' hazelnuts were found as 11.87%, 12.61% and 17.68% for nuts roasted at 540 W, unroasted and those roasted at 720 W, respectively. It was observed that K (9735.1 mg/kg) and Mg (2343.7 mg/kg) contents of the investigated samples were found at the maximum levels in unroasted 'Tombul' hazelnut, while the highest P (2845.0 mg/kg) and S (1795.3 mg/kg) contents are determined for hazelnut roasted at 720 W (p < 0.05). The highest Ca content in hazelnut kernel was also observed at 360 W with 2400.9 mg/kg. However, roasting process did not dramatically affect the mineral contents of samples.

The influence of fermentation and bud sizes on antioxidant activity and bioactive compounds of three different size buds of Capparis ovata Desf. var. canescens plant.

The impact of fermentation and bud size on the antioxidant activity, total phenolic content (TPC), and bioactive compounds of caper buds were investigated. The results showed significant differences in the bioactive properties depending on bud sizes and fermentation process. Antioxidant activity values of fresh caper buds were ranged between 69.61% (bid size) and 72.78% (small size), whereas the values of fermented ones varied between 12.50% (big size) and 39.09% (small size). TPC of fresh caper buds were found in the range of 357.81 mg GAE/100 g (medium size) and 372.22 mg GAE/100 g (small size), while those of fermented buds were ranged from 167.53 mg GAE/100 g (medium) to 246.01 mg GAE/100 g (small). Apigenin-7-glucoside, (+)-catechin, 1,2-dihydroxybenzene, and 3,4-dihydroxybenzoic, syringic, and gallic acids were the major phenolic compounds in both fresh and fermented caper buds. Overall, this study clearly demonstrated that both fermentation process and bud size significantly affected the antioxidant activity, TPC, and phenolic compounds of caper buds.

Effect of sonication process of terebinth (Pistacia terebinthus L.) fruits on antioxidant activity, phenolic compounds, fatty acids and tocopherol contents.

The current study investigated the impact of sonication process on antioxidant activity, phenolic compounds, total phenolic, total flavonoid, oil contents, fatty acids profile, and tocopherols of terebinth (Pistacia terebinthus) fruits. The highest antioxidant activity (87.32%), total phenolic (251.25 mg/100 g) and flavonoid (3413.72 mg/100 g) contents were observed in terebinth fruits sonicated for 30 min. The oil contents of terebinth increased from 38.93% (control) to 42.60% (sonicated for 15 min) after sonication process. The quercetin and catechin were the chief phenolic compounds in P. terebinthus extracts and their values were increased from 129.09 to 467.28 mg/100 g (quercetin) and from 5.58 to 21.33 mg/100 g (catechin) in fruits sonicated for 30 min. The major fatty acids of terebinth fruit oil were oleic (48.02-49.15%), linoleic (22.28-23.48%) and palmitic (22.10-23.67%) and sonication processes did not affect the quantities of these fatty acids. γ-Tocopherol was the most abundant isomer with the value of 63.95-122.03 mg/100 g in terebinth fruit oil. It could be concluded that pre-sonication for 30 min was more suitable for enhancing the antioxidants and phenolic compounds of P. terebinthus fruit.

Characterization of Oil Uptake and Fatty Acid Composition of Pre-treated Potato Slices Fried in Sunflower and Olive Oils.

In this study, the oil uptake and fatty acid composition of fried potato slices were determined. Some pre-treatments such as blanching, freezing, and blanching-freezing were applied to potato slices before frying while the untreated samples were used as a control. The frying process was carried out in sunflower and olive oils. The percentage oil uptake in slices varied from 4.26% to 10.35% when fried in sunflower oil. In the case of the control samples slices fried in olive oil contained high monounsaturated fatty acid (oleic acid) content (5.45%), and lesser oil uptake was observed than those processed in sunflower oil, which is rich in polyunsaturated fatty acid (linoleic acid is 5.99%) (p < 0.05). The oil uptake was also compared in the case of potato slices fried in two different oils after pre-treatments. The maximum oil uptake was observed in the case of blanched-frozen potatoes, whereas minimum oil uptake was observed in frozen only slices for both oils. The fatty acid contents in oils extracted from fried potato slices showed that the predominant fatty acids were palmitic, stearic, oleic, and linoleic acids. The best results were observed in frozen potato slices fried in both sunflower and olive oils.

Effect of microwave and oven drying processes on antioxidant activity, total phenol and phenolic compounds of kiwi and pepino fruits.

Kiwi and pepino fruits are most valuable fruits as they contains substantial amounts of nutrients and bioactive compounds. These fruits exhibited several health potentials such as antioxidant, antiinflammatory, antiobesity, antihyperlipidemia, and anticancer properties. However, studies on the effect of microwave and conventional drying methods on the antioxidant activity and bioactive compounds of kiwi and pepino fruits are limited. Therefore, this study was conducted to assess the effect of microwave and oven drying methods on antioxidant activity, total phenolic, and phenolic compounds of kiwi and pepino fruits. Drying of the fruit samples was carried out using conventional (70 °C for 20 h) and microwave (720 W for 3 min) ovens. 1,1-diphenyl-2-picrylhydrazyl scavenging and colorimetric Folin-Ciocalteu assays were used to assess the antioxidant activity and total phenolic contents, respectively, of fresh and dried fruits. Both drying methods significantly (p < 0.05) decreased the moisture contents of both fruits compared to untreated controls. Concomitantly, drying methods also enhanced (p < 0.05) antioxidant activity and total phenolic content of both fruits with the highest improvement being observed for microwave-dried fruits compared to untreated controls. In addition, a significant increase was observed in catechin and 1,2-dihydroxybenzene content of kiwi and pepino after drying process. However, microwave drying method reduced the amount of 3,4-dihydroxybenzoic acid in kiwi (ranging from 34.120 to 9.350 mg/100 g) and pepino (varied from 33.414 to 15.445 mg/100 g). Generally, the highest antioxidant activity and phenolic contents were reported in microwave oven dried samples, followed by samples dried in oven and fresh fruits. The results revealed that microwave drying could be more useful in fruit drying than conventional drying. In addition, dried kiwi and pepino fruits contains substantial quantities of phenolic compounds with high antioxidant activity compared to fresh fruits, and thus they are considered as healthy food.

The effect of harvest times on bioactive properties and fatty acid compositions of prickly pear (Opuntia ficus-barbarica A. Berger) fruits.

In the study, the impact of harvest time on total phenolic content, antioxidant activity, and phenolic compounds of prickly pear (Opuntia ficus-barbarica A. Berger) fruit pulp and the oil content and fatty acids profile of the seed were investigated. The highest total phenolic content was determined as 156.77 mg/100 g in July 1 harvest, while the maximum antioxidant activity and total oil content were found as 9.81% and 6.80% at the last stage of maturation (15 August), respectively. The highest oleic (28.51%), palmitic (22.61%) and stearic acid contents (9.20%) in seed oil were observed in June 15 harvest. The highest value for linoleic acid (57.50%) was detected in August 15 harvest. Prickly pear is a vital source of bioactive constituents such as phenolic and antioxidant substances in terms of being useful for human health and the optimum harvesting time to retain high quantities of most phenolic compounds is 1st July.