Fahad Al Juhaimi’s research while affiliated with King Saud University and other places

In this study, the concentrations of toxic elements as well as macro- and microelements accumulated in the peel and flesh of different Citrus fruits were investigated by inductively coupled plasma optical emission spectroscopy (ICP-OES). The toxic element found in the highest amounts in the peel and flesh parts of citrus fruits was arsenic (As), followed by barium (Ba), chromium (Cr), and cadmium (Cd) in decreasing order. The quantity of As in citrus fruit peel and flesh parts varied between 5.42 (lemon) and 10.59 mg/kg (grapefruit) to 4.62 (lemon) and 12.25 mg/kg (grapefruit), respectively. The aluminum (Al) and As contents of the peels of citrus fruits (except grapefruit) were high in the flesh parts. The quantities of phosphorus (P) and potassium (K) in the peels of citrus fruits were between 1012.35 (lemon) and 1159.82 mg/kg (grapefruit) to 4340.07 (lemon) and 8695.24 mg/kg (grapefruit), respectively. In addition, while the quantity of P in the fruit flesh parts was between 460.13 (orange) and 1486.49 mg/kg (grapefruit), the quantity of K in the flesh of citrus fruits was between 11082.51 (lemon) and 14585.65 mg/kg (grapefruit). In general, the P contents of the flesh parts of grapefruit and lemon fruits were higher than the peel parts. In addition, while the K contents of the flesh parts of the fruits were established to be high in the shell parts, the amounts of calcium (Ca) and magnesium (Mg) in the flesh parts were found to be low. While the quantity of iron (Fe) in the peel parts of grapefruit, lemon, mandarin, and orange fruits was higher than in the flesh parts, the quantity of zinc (Zn) in the fruits was found to be low. The microelement found in the highest amounts in fruit parts was B, followed by Fe, Mn, and Zn in decreasing order. The toxic element found in the highest amounts in the peel and flesh of citrus fruits was As, followed by Ba, Cr, and Cd in decreasing order.

In this study, the effect of oven and microwave roasting at different times on oil content, total phenol, flavonoid, fatty acids, phenolic components and mineral contents of purslane seeds was investigated. The total phenolic quantities of the purslane seeds roasted in the oven and microwave were characterized to be between 252.0 ± 1.80 (180 °C/5 min in the oven) and 256.6 ± 3.51 (10 min in the oven), and between 216.3 ± 0.28 (720 W/15 min in the microwave) and 203.7 ± 1.93 GAE/100 g (30 min in the microwave), respectively. The highest total flavonoid (613.8 ± 4.36 mg QE/100 g) was detected in the application of roasting in the oven for 10 min. Roasting in the oven for 5 min caused a decrease in the total flavonoid content (584.3 ± 4.95 mg QE/100 g), while roasting for 10 min caused an increase in the flavonoid content (613.8 ± 4.36 mg QE/100 g). The oil yields of purslane seed samples roasted in the oven for 5 min and 10 min were defined as 40.40 ± 0.99% and 45.00 ± 0.71%, respectively. Statistical differences were observed between the oil, total phenol and flavonoid contents of the samples depending on the roasting times in the oven and microwave (p ≤ 0.01). The protein contents of the purslane seeds were established to be between 27.89 ± 0.279% (control) and 37.24 ± 0.407% (10 min in the oven). The calcium (Ca) contents of the purslane seeds changed between 8314.99 ± 327.53 ppm (5 min in the oven) and 4340.62 ± 498.45 ppm (15 min in the microwave), while the phosphorus contents varied between 4905.13 ± 43.02 ppm (15 min in the microwave) and 4051.23 ± 6.39 ppm (unroasted). In addition, the potassium content was found to be between 4565.89 ± 153.47 (5 min in the oven) and 3904.02 ± 7.17 ppm (unroasted). It was also observed that the purslane seeds roasted in the oven for 10 min maintained a linolenic fatty acid content of up to 65.57%. Considering the bioactive properties and phytochemical components of purslane seeds roasted in both roasting systems, they are important in terms of the nutritional enrichment of foods as a food supplement.

In this study, the effect of microwave drying on oil content, bioactive compounds, antioxidant activity, polyphenols and fatty acid profiles of fresh (control) and dried plum kernels was investigated. The oil quantities of plum seeds dried were found between 27.40% (control) and 42.42% (900 W). Total phenolic and flavonoid values of fresh (control) and dried-plum seeds were assessed to be between 9.77 (control) and 41.66 mgGAE/100 g (900 w) to 6.90 (control) and 23.67 mg/100 g (900 W), respectively. Total phenol and flavonoid quantities of the plum seeds dried at 900 W were slightly higher than those of the plum seeds dried at 720 W. L* (brightness) values of plum seeds changed between 55.97 and 59.62. Roasting in the microwave oven at 720 W was decreased the L* values of samples, while L* value of sample roasted at 900 W was closed to control. Gallic and 3,4-dihydroxybenzoic acid values of plum kernel samples were assigned to be between 1.19 (720 W) and 2.01 mg/100 g (900 W) to 0.22 (control) and 7.09 mg/100 g (900 W), respectively. Also, catechin and rutin quantities of plum seeds were established between 0.20 (control) and 7.55 mg/100 g (900 W) to 1.42 (control) and 3.59 mg/100 g (900 W), respectively. In general, the amount of phenolic compounds of plum seeds dried at every two watts showed an increase (except quercetin) compared to the control. Only the amount of quercetin decreased partially in the dried samples. While oleic acid quantities of raw (control) and dried plum kernel oils are reported between 68.28% (720 W) and 71.60% (900 W), linoleic acid amounts of plum kernel oils were found between 20.77% (900 W) and 23.49% (720 W). The quantities of saturated fatty acids in plum kernel oils were found to be quite low compared to the content of unsaturated fatty acids. graphical abstract Fullsize Image

In this study, the total phenol, total flavonoid content, antioxidant capacity, phenolic component and fatty acid profiles of caper seed oils extracted by solvent extraction, sonication extraction and cold press methods were revealed. Total phenol amounts of caper seed oils extracted by cold press, sonication and solvent systems were recorded as 0.10, 0.11 and 0.16 mg GAE/100 g, respectively. There was no statistically significant differences between the total phenol values of caper seed oils provided by sonication and cold press systems (p > 0.05). While the flavonoid amount of the oil extracted from caper seeds by solvent extraction system is determined as 358.9 mg CE/100 g, the total flavonoid amounts of caper seed oils extracted by sonication and cold pressing methods were established as 194.6 and 83.9 mgCE/100 g, respectively. The highest antioxidant capacity was established in the oil provided by solvent extraction (1.456%), followed by ultrasonic extraction (1.453%) and cold press oil (1.448%) in decreasing order. The dominant phenolic components of caper seed oils were quercetin, kaempferol, gallic acid, resveratrol and catechin. The fatty acid detected at the highest value in caper oils extracted by different extraction systems was linoleic acid (61.16-62.74%), followed by oleic, palmitic and stearic acids in decreasing order. Other fatty acids were recorded at low levels. As a result, it can be said that the caper oil extracted by solvent extraction is richer in quercetin and linoleic acid. graphical abstract Fullsize Image

In this study, the effects of roasting at different times in hot air and microwave oven on the bioactive properties, fatty acid compositions, mineral contents and phenolic components of pine nut kernels and oils were investigated. According to the results obtained, the moisture quantity of pine nuts generally decreased due to roasting. The lowest moisture content belongs to the sample roasted for 17 min in a microwave oven with 2.66%. Roasting processes on oil content gave positive results, and the sample that provides the highest content (48.4%) is the sample that was roasted for 7 min in hot air. Roasting processes increased the protein content in general, and the samples with the highest protein content were roasted in a microwave oven for 17 min (26.16%). When the ash content is examined, it has been determined that the oven and microwave oven roasting processes reduce the amount of ash. While the total phenol content of the kernels increased inversely with the roasting times, the total phenol content of the oils increased unevenly depending on the roasting times compared to the control sample. Gallic acid is the most frequently detected phenolic component in pine nut kernels and oils. The highest flavonoid content in the kernels was measured with 9 min roasting (12.81 mgqE /100 g) in the microwave oven, while roasting for 7 min in the oven gave the lowest value (7.86 mgqE /100 g). On the other hand, the highest value in oils with 20.6 mgqE /100 g belongs to the samples roasted in an oven for 7 min. In general, the antioxidant activity value of pine nut kernels roasted in an oven and microwave oven showed a partial increase compared to the control. The antioxidant activity values of the oils gave similar results and it was seen that the results were not affected by the roasting times. The most frequently detected minerals in pine nut samples were N, P, K, Mg, S, Ca, Fe, Zn, Mn, Cu and B, in decreasing order. The most abundant fatty acids in pine nut oils were linoleic and oleic acids, and roasting had a slight negative effect on the fatty acid composition.

In this study, the effect of dehydration of some physico‐chemical characteristics, total phenol, flavonoids, antioxidant capacity and phenolic compounds of green and red jalapeno pepper fruits was investigated. The total carotenoid contents of red and green jalapeno pepper samples were reported to be between 14.15 (fresh) and 129.00 μg/g (540 and 720 W) to 2.8 (fresh) and 27.25 μg/g (720 W), respectively. Total phenolic results of red and green jalapeno pepper samples were recorded between 205.83 (fresh) and 343.93 mg GAE/100 g (540 W) to 81.69 (fresh) and 309.88 mg gallic acid equivalent (GAE)/100 g (air drying), respectively. The highest decrease in L* results (brightness) of both red (32.33) and green (36.45) peppers was determined with air drying. Gallic acid, catechin and kaempferol were the predominant phenolic compounds of jalapeno peppers. Gallic acid amounts of red and green jalapeno pepper samples changed between 3.23 (fresh) and 16.20 mg/100 g (air) to 2.41 (fresh) and 9.30 mg/100 g (air), respectively. Also, catechin amounts of both red and green dehydrated jalapeno pepper fruits were determined between 3.24 (fresh) and 106.33 mg/100 g (900 W) to 2.89 (fresh) and 90.05 mg/100 g (air), respectively. Both conventional and microwave drying has caused the reduction of redness for red pepper and greenness for green pepper. The phenolic components of red jalapeno peppers were partially higher than the green ones.

In this study, the effects of different germination times on some chemical characteristics, total phenol and flavonoid quantity, antioxidant capacities, phenolic and fatty acid compositions and biogenic element contents of tigernut tubers were investigated. Total phenolic and flavonoid quantities of raw and tigernut tubers germinated at certain germination periods were reported to be between 24.40 (first period of germination) and 63.84 mgGAE/100 g (third period of germination) to 33.00 (control) and 184.24 mgRE/100 g (third period of germination), respectively. Antioxidant capacities of raw and germinated tigernut tubers were recorded to be between 0.91 (first period of germination) and 1.57 mmolTE kg⁻¹ (third period of germination). Gallic (except control), catechin, caffeic acid, rutin and kaempferol values of tubers were higher especially in the second and third periods of germination compared to the first period of control and germination. Oleic and linoleic acid values of raw (control) and germinated tigernut oils were identified between 69.41% (third period of germination) and 72.53% (control) to 9.77 (control) and 11.77% (third period of germination), respectively. P, K, Ca, Mg, S and Na were the dominant elements of raw and germinated tigernuts. The bioactive properties, phenolic component amounts and element quantities of germinated tubers were increased.

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. 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.

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 (Taşucu-Mersin) to 1343.60 (Konya) and 184.53 mg/100 g (Taşucu-Mersin), respectively. Total phenol contents and antioxidant activity values of Acacia seeds were identified as 255.11 (Konya) and 190.00 mgGAE/Taşucu-Mersin) to 64.18% (Konya) and 75.21% (Taşucu-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 (Taşucu-Mersin), (+)-catechin contents of Acacia seeds were identified as 3.42 (Konya) and 9.51 mg/100 g (Taşucu-Mersin). Also, rutintrihydrate and ferulic contents of Acacia seeds were found as 23.37 (Konya) and 11.87 mg/100 g (Taşucu-Mersin) to 14.74 mg/100 g (Konya) and 1.12 mg/100 g (Taşucu-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. graphical abstract Fullsize Image

The protein amounts of chia seeds were determined between 27.56% (control) and 28.37% (boiled). Total phenolic and antioxidant activity values of chia seeds treated by several applications changed between 237.70 mgGAE/100g (germinated) and 535 mgGAE/100g (roasted) to 15.27 mmol/kg (roasted) and 15.50 mmol/kg (germinated), respectively. While (+)-catechin amounts of seeds are determined between 15.47 (control) and 60.95 mg/100g (roasted), rutintrihydrate contents of seed extracts were identified between 3.98 mg/100g (control) and 24.92 mg/100g(roasted). While linolenic acid values of oils vary between 62.89% (germinated) and 66.76% (rpasted), linoleic acid amounts of oil samples were identified between 18.55% (control) and 21.04% (roasted). While P contents of chia seeds change between 6103.58 mg/kg(boiled) and 7253.45 mg/kg (control), K amounts of seeds varied between 2534.48 mg/kg (germinated) and 5351.58 mg/kg(roasted). In general, it was observed that the mineral content of boiled chia seeds was low compared to the control and other treated seeds.