• Applied Chemistry for Engineering
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• v.25 no.6
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• pp.619-623
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• 2014

The acid hydrolysis and enzymatic saccharification were carried out for the production of cellulosic ethanol. The possibility of bio-energy production from tangerine peel and apple and watermelon rind was evaluated by determining the optimum production condition. The optimum conditions for the production of cellulosic ethanol from fruit peel were as follows: the sulfuric acid concentration and reaction time of acid hydrolysis for the ethanol production from an apple rind were 20 wt% and 90 min, respectively. The concentration of sulfuric acid for tangerine peel and a watermelon rind at the hydrolysis time of 60 min were 15 wt% and 10 wt%, respectively. A viscozyme was proven as the best conversion for the ethanol production when using enzymatic saccharification from fruit peels. The optimum enzymatic saccharification time for tangerine peel and apple and watermelon rind were 60, 180, and 120 min, respectively.

• Applied Chemistry for Engineering
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• v.20 no.5
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• pp.542-546
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• 2009

Methane production using the mixed organic wastes of peel-type fruit wastes from apple or orange and sewage sludge was investigated in the batch anaerobic degradation process. When apple or orange peels with sewage sludge were used as mixed substrates, higher methane production was achieved under the condition of 3 : 7 (fruit peel : sewage sludge) mixing ratio. However, above the 3 : 7 mixing ratio, the pH of mixture was decreased from 8.0 to 4.5~4.7 due to organic acid production from the fruit wastes. Subsequently, methane production was low. The results in this study could be effectively applied to the methane gas production system as a bioenergy in the mixed batch anaerobic digestion process using the peel-type fruit wastes and sewage sludge.

• Textile Coloration and Finishing
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• v.32 no.4
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• pp.193-198
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• 2020

In this study, the validity of extracts from food waste as biocatalyst for indigo reduction was examined. Dried food wastes such as apple peel and corn waste were water-extracted and freeze-dried. The reducing power of extracts for indigo was evaluated by the oxidation-reduction potential(ORP) measurement of reduction bath and color strength(K/S value) of the fabrics dyed in the indigo reduction bath. Total sugar contents of the apple peel and corn waste extracts were 60.56% and 62.36%, respectively. Antioxidant activity was 64.78% for the extract of apple peel and 7.96% for the extract of corn waste. Indigo reduction took place quickly with both extracts, and maximum color strength was obtained up to 15.91 and 12.11 within 1-3 days, respectively. The oxidation-reduction potential of reduction bath was stabilized in the range of -500 ~ -620 mV according to the kinds of food waste and the extract concentration. At higher concentration of the extracts, reduction power was maintained for longer time and stronger color strength was obtained. Compared to sodium dithionite, the reducing power of the studied extracts was lower, but the reduction stability was superior to it. The studied extracts were effective biocatalyst as biodegradable and safe alternatives to sodium dithionite for indigo reduction.

• Korean journal of food and cookery science
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• v.27 no.2
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• pp.111-123
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• 2011

The purpose of this study was to investigate the quality characteristics of Sulgidduk prepared by adding the optimal amount of apple powder. Five different mixture ratios of apple powder to rice flour were prepared (0, 4, 8, 12, and 16%). After being stored for 3 days, the mixtures of apple powder and rice flour were measured to determine moisture content, color values, sensory qualities, and the mechanical texture characteristics of Sulgidduk. Moisture content of Sulgidduk with added apple powder ranged from 36% to 39% and but decreased with significantly with added apple powder. The L-color value decreased, whereas both the a-and b-values increased as apple powder was added. Thus, apple peel likely affected the Sulgidduk color value. The pH of Sulgidduk decreased with the addition of apple powder, whereas sugar level increased as apple powder was added. In the mechanical evaluation of apple Sulgidduk, hardness was significantly higher during the 3 days of storage with increasing amounts of added apple powder. Cohesiveness increased significantly during the storage period with the addition of apple powder,-; however, it began to decreased after 3 days. Springiness increased significantly with the addition of apple powder. Both adhesiveness and chewiness of Sulgidduk increased with added apple powder. Sensory quality characteristics such as color, taste, flavor, and moistness were improved with increasing amounts of added apple powder. However, the sensory quality of Sulgidduk decreased when the ratio of apple powder to rice flour was greater than 25%. Consequently, a mixture of 15~20% apple powder to rice flour was the best formula for improving Sulgidduk in terms of sensory quality.

• Korean Journal of Food Science and Technology
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• v.45 no.5
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• pp.598-604
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• 2013

This study was designed to evaluate the usability of the following citrus peel extracts (CPEs): Citrus sinensis (orange), C. unshiu (mandarin orange), C. limon (lemon), and C. paradise (grapefruit) as natural antibrowning agents. Overall, 0.1% of the CPEs were effective in reducing the browning of apple slices. The appearance of apple slices dipped in C. limon peel extracts (LPE) were found to be excellent and their Hunter L and ${\Delta}E$ values were similar to the values obtained when apple slices were dipped in ascorbic acid. The pH values of the different CPEs were not significantly different from each other, but were higher than that of ascorbic acid. LPE was found to possess the highest total phenolic content, flavonoid content, DPPH radical scavenging activity, and copper ($Cu^{2+}$) chelating activity. All these results suggest that citrus peel extracts, especially lemon peel extract, can be used as natural antibrowning agents.

• Journal of the Korean Society of Food Science and Nutrition
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• v.41 no.9
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• pp.1305-1309
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• 2012

For functional enhancement of apples, the effects of CuEDTA and FeEDTA foliar spray were investigated on the antioxidant contents and antioxidant activities in 'Hongro' fruit, which is a representative early season harvesting apple cultivar, at 30 days before harvest. The polyphenolic content of peel was significantly higher in the CuEDTA (1,228.6 mg/100 g) and FeEDTA (1,210.0 mg/100 g) spraying treatment groups compared to the control group (998.8 mg/100 g). The flavonoid content of peel showed the same trend as that of polyphenolic content. The ascorbic acid content of peel as also significantly increased in the CuEDTA and FeEDTA spraying treatment groups, but anthocyanin content was the highest in the control group (560.6 mg/100 g). The ABTS and DPPH radical scavenging activities were higher in the CuEDTA and FeEDTA spraying treatment groups than in the control group, but reducing power was not significantly different between the treatments. As a result of this study, 3% CuEDTA and FeEDTA spraying treatments at 30 days before harvest can be used to effectively enhance antioxidant contents in 'Hongro' apple.

• Food Engineering Progress
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• v.21 no.4
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• pp.326-331
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• 2017

A cultivar (Malus domestica cv. Fuji) of apple was selected to make apple peel (AP) powder by three different powdering methods. Frozen AP was thawed and subsequently was dried or ground without drying. After AP was dried by hot-air drying at $60^{\circ}C$ or freeze-drying, the dried AP was ground using a conventional blender. Separately, the thawed AP was powered by using a cryogenic micro grinding technology (CMGT). The ground AP and three types of AP powder were extracted using deionized water, 20, 40, 60, 80, or 100% methanol, followed by vacuum evaporation. The total phenolics contents (TPC), total flavonoids contents (TFC), DPPH, and ABTS radical scavenging capacities of each extract were compared to determine an efficient powdering method. Lyophilized AP powder extract using 60% methanol showed the highest TPC and DPPH radical scavenging capacity. In contrast, 60% methanol extract of the powder by CMGT, resulting in the smallest particle, exhibited the highest TFC and ABTS radical scavenging capacity. This study suggests that the extraction yield of bioactive compounds from AP may be varied according to different powdering methods and that a new powdering process such as CMGT may be applicable to develop functional foods efficiently.

• Food Science and Preservation
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• v.6 no.1
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• pp.29-36
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• 1999

Using Fuji apple fruits cultivated in Kyungpook prefecture, the calibration model for firmness evaluation of fruits by near infrared(NIR) reflectance spectroscopy was developed, and the various influence factors such as instrument variety, measuring method, sample group, apple peel and selection of firmness point were investigated. Spectra of sample were recorded in wavelength range of 1100∼2500nm using NIR spectrometer (InfraAlyzer 500), and data were analyzed by stepwise multiple linear regression of IDAS program. The accuracy of calibration model was the highest when using sample group with wide range, and the firmness mean values obtained in graph by texture analyser(TA) were used as standard data. Chemometrics models were developed using a calibration set of 324 samples and an independent validation set of 216 samples to evaluate the predictive ability of the models. The correlation coefficients and standard error of prediction were 0.84 and 0.094kg, respectively. Using developed calibration model, it was possible to monitor the firmness change of fruits during storage frequently. Time, which was reached to firmness high value in graph by TA, is possible to use as new parameter for freshness of fruit surface during storage.

• Journal of the Korean Applied Science and Technology
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• v.33 no.1
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• pp.186-194
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• 2016

Consumption of fruits and vegetables has been conducted to be effective in the prevention of chronic diseases. In this study, 70% methanol, 70% ethanol and chloroform-methanol mixture (CM, 2:1, v/v) were used as solvents in the extraction of apple peels. The total phenol content, total flavonoid content and antioxidant activity of various extracts were investigated using in vitro assays. The extract obtained by 70% methanol showed the highest total phenol content ($20.87{\pm}0.17mgCAE/g$), ABTS [2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt] radical scavenging activity and ferric reducing antioxidant power. However, 70% ethanol extract possessed the strongest antioxidant activity assayed by DPPH (2,2-diphenyl-1-picrylhydrazyl) radical scavenging activity and ${\beta}$-carotene bleaching method. And CM extract was found to show the highest total flavonoid content with the value of $9.26{\pm}0.06mgQE/g$. These results indicated that apple peels can be used in dietary applications with a potential to reduce oxidative stress.

• Food Science and Preservation
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• v.7 no.2
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• pp.133-138
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• 2000

The research was conducted to measure the effect of temperature on respiratory and quality characteristics of 'Tsugaru' apple(Malus domestica Borkh) during storage at 4$^{\circ}$C, 10$^{\circ}$C and 20$^{\circ}$C. Respiration rate of the apple just after harvest was 7.57 mL CO$_2$/kg/h at 20$^{\circ}$C. It was decreased rapidly and was 2.86 mL CO$_2$/kg/h after storage for 45 days at 20$^{\circ}$C. The apples showed the highest ethylene production rate at 10$^{\circ}$C and 20$^{\circ}$C after 14 days, and at 4$^{\circ}$C after 28 days during storage. Weight of the apple was reduced by 2.9% after 120 days at 4$^{\circ}$C and by 6.1% after 45 days at 20$^{\circ}$C. Color difference of peel and pH increased with the temperatures but titratable acidity and flesh firmness showed the reverse trends during storage. According to the subjective quality test, it could be suggested that the shelf-life of the apple is 86 days at 4$^{\circ}$C, 65 days at 10$^{\circ}$C and 37 days at 20$^{\circ}$C, respectively.