Nyam Lin - Academia.edu (original) (raw)

Papers by Nyam Lin

Lwt - Food Science and Technology, 2009

The physicochemical properties and chemical composition of oil extracted from five varieties of p... more The physicochemical properties and chemical composition of oil extracted from five varieties of plant seeds (bittermelon, Kalahari melon, kenaf, pumpkin and roselle seeds) were examined by established methods. The thermal properties of extracted oils by differential scanning calorimetry were also evaluated. Sensorial profiles of these seed oils were defined through the CieLab (L*, a*, b*) colour. Most of the quality indices and fatty acid compositions showed significant (P < 0.05) variations among the extracted oils. Physicochemical properties of the oils extracted were iodine value, 86.0-125.0 g I 2 /100 g oil; saponification value, 171.0-190.7 mg of KOH/g of oil; acid value, 1.1-12.9 mg of KOH/g of oil, free fatty acid, 0.6-6.5 g/100 g of oil, and peroxide value 1.5-6.5 meq of O 2 /kg of oil. Palmitic, oleic and linoleic acids were the major fatty acids in all of the extracted seed oils except for bittermelon, where eleostearic acid was the major fatty acid. Gallic, protocatechuic, p-hydroxybenzoic, vanillic, caffeic, syringic, pcoumaric and ferulic acids were identified in the extracted plant oils. Among these, vanillic acid was predominant in all extracted oils. The oils were rich in tocopherols with g-tocopherol as the major components in all oil samples. Among the phytosterols, sitosterol was the major phytosterol extracted from the five plant seed oils. The seeds of these plants contain a great number of valuable minor compounds, which have a potential high value as food and for production of non-food products.

Food and Bioproducts Processing, 2010

Recovery of phytosterol from roselle (Hibiscus sabdariffa L.) seeds via supercritical carbon diox... more Recovery of phytosterol from roselle (Hibiscus sabdariffa L.) seeds via supercritical carbon dioxide extraction modified with ethanol was investigated at pressures of 200–400bar, temperatures from 40 to 80°C and at supercritical fluid flow rates from 10 to 20ml/min. It was found that an entrainer such as ethanol could enhance the solubility and extraction yield of roselle seed oil from the

Journal of The American Oil Chemists Society, 2009

Enzymatic extraction of oil from Kalahari melon seeds was investigated and evaluated by response ... more Enzymatic extraction of oil from Kalahari melon seeds was investigated and evaluated by response surface methodology (RSM). Two commercial protease enzyme products were used separately: Neutrase® 0.8 L and Flavourzyme® 1000 L from Novozymes (Bagsvaerd, Denmark). RSM was applied to model and optimize the reaction conditions namely concentration of enzyme (20–50 g kg−1 of seed mass), initial pH of mixture (pH 5–9), incubation temperature (40–60 °C), and incubation time (12–36 h). Well fitting models were successfully established for both enzymes: Neutrase 0.8 L (R 2 = 0.9410) and Flavourzyme 1000 L (R 2 = 0.9574) through multiple linear regressions with backward elimination. Incubation time was the most significant reaction factor on oil yield for both enzymes. The optimal conditions for Neutrase 0.8 L were: an enzyme concentration of 25 g kg−1, an initial pH of 7, a temperature at 58 °C and an incubation time of 31 h with constant shaking at 100 rpm. Centrifuging the mixture at 8,000g for 20 min separated the oil with a recovery of 68.58 ± 3.39%. The optimal conditions for Flavourzyme 1000 L were enzyme concentration of 21 g kg−1, initial pH of 6, temperature at 50 °C and incubation time of 36 h. These optimum conditions yielded a 71.55 ± 1.28% oil recovery.

Food Chemistry, 2010

Tocopherol-enriched oil was extracted by supercritical fluid extraction of carbon dioxide (SFE-CO... more Tocopherol-enriched oil was extracted by supercritical fluid extraction of carbon dioxide (SFE-CO2) from Kalahari melon and roselle seeds. The SFE-CO2 process was optimised using response surface methodology (RSM) with central composite design (CCD). Three SFE-CO2 parameters namely extracting pressure, extracting temperature, and flow rate of carbon dioxide were examined. The optimal SFE-CO2 conditions were determined and the quadratic response surfaces

Food and Bioprocess Technology

Supercritical carbon dioxide (SC-CO2) extraction of oil from Kalahari melon seeds was investigate... more Supercritical carbon dioxide (SC-CO2) extraction of oil from Kalahari melon seeds was investigated in this study. Response surface methodology was applied to model and optimize the extraction, namely pressure (200–400 bar), temperature (40–80 °C), and supercritical fluid flow rate (10–20 mL/min). Well-fitting models were successfully established for oil recovery (R 2 = 0.9672) and phytosterol concentration (milligrams per 100 g; R 2 = 0.8150) through multiple linear regressions with backward elimination. The effect of supercritical fluid flow rate was the most significant (P < 0.05) factor that affected oil recovery but this factor had no significant (P > 0.05) effect on phytosterol concentration. The optimal processing conditions for oil recovery and phytosterol concentration were pressure of 300 bar, temperature at 40 °C, and supercritical fluid flow rate of 12 mL/min. These optimal conditions yielded a 76.3% oil recovery and 836.5 mg/100 g of phytosterol concentration. The oil content in the Kalahari melon seeds as estimated by Soxhlet extraction was around 30.5/100 g. The phytosterol concentration in the oil extracted with SC-CO2 extraction was 94% higher than that obtained with solvent extraction.

Lwt - Food Science and Technology, 2009

The physicochemical properties and chemical composition of oil extracted from five varieties of p... more The physicochemical properties and chemical composition of oil extracted from five varieties of plant seeds (bittermelon, Kalahari melon, kenaf, pumpkin and roselle seeds) were examined by established methods. The thermal properties of extracted oils by differential scanning calorimetry were also evaluated. Sensorial profiles of these seed oils were defined through the CieLab (L*, a*, b*) colour. Most of the quality indices and fatty acid compositions showed significant (P < 0.05) variations among the extracted oils. Physicochemical properties of the oils extracted were iodine value, 86.0-125.0 g I 2 /100 g oil; saponification value, 171.0-190.7 mg of KOH/g of oil; acid value, 1.1-12.9 mg of KOH/g of oil, free fatty acid, 0.6-6.5 g/100 g of oil, and peroxide value 1.5-6.5 meq of O 2 /kg of oil. Palmitic, oleic and linoleic acids were the major fatty acids in all of the extracted seed oils except for bittermelon, where eleostearic acid was the major fatty acid. Gallic, protocatechuic, p-hydroxybenzoic, vanillic, caffeic, syringic, pcoumaric and ferulic acids were identified in the extracted plant oils. Among these, vanillic acid was predominant in all extracted oils. The oils were rich in tocopherols with g-tocopherol as the major components in all oil samples. Among the phytosterols, sitosterol was the major phytosterol extracted from the five plant seed oils. The seeds of these plants contain a great number of valuable minor compounds, which have a potential high value as food and for production of non-food products.

Food and Bioproducts Processing, 2010

Recovery of phytosterol from roselle (Hibiscus sabdariffa L.) seeds via supercritical carbon diox... more Recovery of phytosterol from roselle (Hibiscus sabdariffa L.) seeds via supercritical carbon dioxide extraction modified with ethanol was investigated at pressures of 200–400bar, temperatures from 40 to 80°C and at supercritical fluid flow rates from 10 to 20ml/min. It was found that an entrainer such as ethanol could enhance the solubility and extraction yield of roselle seed oil from the

Journal of The American Oil Chemists Society, 2009

Enzymatic extraction of oil from Kalahari melon seeds was investigated and evaluated by response ... more Enzymatic extraction of oil from Kalahari melon seeds was investigated and evaluated by response surface methodology (RSM). Two commercial protease enzyme products were used separately: Neutrase® 0.8 L and Flavourzyme® 1000 L from Novozymes (Bagsvaerd, Denmark). RSM was applied to model and optimize the reaction conditions namely concentration of enzyme (20–50 g kg−1 of seed mass), initial pH of mixture (pH 5–9), incubation temperature (40–60 °C), and incubation time (12–36 h). Well fitting models were successfully established for both enzymes: Neutrase 0.8 L (R 2 = 0.9410) and Flavourzyme 1000 L (R 2 = 0.9574) through multiple linear regressions with backward elimination. Incubation time was the most significant reaction factor on oil yield for both enzymes. The optimal conditions for Neutrase 0.8 L were: an enzyme concentration of 25 g kg−1, an initial pH of 7, a temperature at 58 °C and an incubation time of 31 h with constant shaking at 100 rpm. Centrifuging the mixture at 8,000g for 20 min separated the oil with a recovery of 68.58 ± 3.39%. The optimal conditions for Flavourzyme 1000 L were enzyme concentration of 21 g kg−1, initial pH of 6, temperature at 50 °C and incubation time of 36 h. These optimum conditions yielded a 71.55 ± 1.28% oil recovery.

Food Chemistry, 2010

Tocopherol-enriched oil was extracted by supercritical fluid extraction of carbon dioxide (SFE-CO... more Tocopherol-enriched oil was extracted by supercritical fluid extraction of carbon dioxide (SFE-CO2) from Kalahari melon and roselle seeds. The SFE-CO2 process was optimised using response surface methodology (RSM) with central composite design (CCD). Three SFE-CO2 parameters namely extracting pressure, extracting temperature, and flow rate of carbon dioxide were examined. The optimal SFE-CO2 conditions were determined and the quadratic response surfaces

Food and Bioprocess Technology

Supercritical carbon dioxide (SC-CO2) extraction of oil from Kalahari melon seeds was investigate... more Supercritical carbon dioxide (SC-CO2) extraction of oil from Kalahari melon seeds was investigated in this study. Response surface methodology was applied to model and optimize the extraction, namely pressure (200–400 bar), temperature (40–80 °C), and supercritical fluid flow rate (10–20 mL/min). Well-fitting models were successfully established for oil recovery (R 2 = 0.9672) and phytosterol concentration (milligrams per 100 g; R 2 = 0.8150) through multiple linear regressions with backward elimination. The effect of supercritical fluid flow rate was the most significant (P < 0.05) factor that affected oil recovery but this factor had no significant (P > 0.05) effect on phytosterol concentration. The optimal processing conditions for oil recovery and phytosterol concentration were pressure of 300 bar, temperature at 40 °C, and supercritical fluid flow rate of 12 mL/min. These optimal conditions yielded a 76.3% oil recovery and 836.5 mg/100 g of phytosterol concentration. The oil content in the Kalahari melon seeds as estimated by Soxhlet extraction was around 30.5/100 g. The phytosterol concentration in the oil extracted with SC-CO2 extraction was 94% higher than that obtained with solvent extraction.