This work involves the development of a novel waste-derived carbon dots (CDs) conjugated with silver (Ag) nanohybrid system-based Fluorescence Resonance Energy Transfer (FRET) sensor for the detection of melamine. CDs and Ag nanoparticles served as energy donors and energy acceptors, respectively. CDs were synthesized from orange peel waste through a combined hydrothermal and ultra-sonication route. The synthesized CDs had hydroxyl, amino, and carboxyl groups on their surface, explaining that waste-derived CDs can act as reducing and stabilizing agents and showed strong absorption and fluorescence emission at 305 and 460 nm, respectively. The bandgap, linear refractive index, conduction band, and valance band potential of CDs were observed to be 2.86, 1.849, 1.14, and 4.002 eV, respectively. No significant difference was observed in the fluorescence properties at different pH (acid and alkaline) and ionic concentrations. Given their fluorescent nature, the synthesized CDs were used for the detection of melamine. The fluorescence of CDs was found to be quenched by Ag+ due to the FRET energy transfer between CDs to Ag. Notably, the zeta potential of Ag@CDs was changed from − 28.7 mV to − 30.6 mV after the incorporation of Ag+. Ag@CDs showed excellent selectivity and sensitivity toward the sensing of melamine in the aqueous solutions with the limit of detection ~ 0.85 μM. Increasing the melamine level also raises the FL intensity of Ag@CDs. The substrate was effectively used in the detection of melamine in milk as a real application and the recovery percentage was found to be 98.03%. Moreover, other adulterants such as urea and formaldehyde can be detected selectively by Ag@CDs. Overall, the synthesized Ag@CDs can be used as an efficient material for sensing applications involving such food adulterants.

The aim of this study was to prepare rice straw silage using cabbage by-product and persimmon peel which are agricultural by-products produced during the same season in Korea. The treatments comprised a commercial corn silage as the control and four rice straw silages (P15-1, P15-2, P30-1, and P30-2) with different levels of persimmon peel supplementation (15%, 30%) and ensiled periods (1 or 2 months). The cabbage by-products were used to adjust silage moisture (approximately 65%). The quality of the experimental silages was evaluated based on organic acid content, palatability to three Holstein dairy cows, and manufacturing cost. In the corn silage, all chemical compositions, except total digestible nutrients and levels of lactic and butyric acids, were significantly (p<0.05) higher than those of the rice straw silages. However, considering the quality analysis using Flieg's score, the rice straw silage supplemented with 30% persimmon peel ensiled for 2 months (P30-2) was estimated as second grade to corn silage, and was relatively better in palatability to dairy cows than the other rice straw silages, which were considered third grade. The manufacturing cost of rice straw silages using cabbage by-product and persimmon peel compared to that of corn silage was reduced by 28%. Consequently, to prepare rice straw silage adjusted to 65% moisture using only cabbage by-products without inoculant, 30% of persimmon peel, 10% of ground corn, and 2% of molasses as a sugar source should be ensiled for at least 2 months.

This study investigated durian (Durio zibethinus) peels to produce powdered activated carbon (DPAC). The influence of process variables such as carbonization temperature, activation time, contact time, CO2 flow rate, and adsorption dosage was optimized using response surface methodology (RSM). A six-factor and two levels Box–Behnken design (BBD) was used to optimize the parameters. The independent variables were activation temperature (°C), duration (min), CO2 flow rate during the activation process (L/min), irradiation of adsorbent (kGy), irradiation duration (min), and adsorbent dosage (g) while phenol removal (mg/L) was the dependent variable (response). Following the observed correlation coefficient values, the design was fitted to a quadratic model (R2 = 0.9896). The optimal removal efficiency (97.25%) was observed at an activation temperature of 900 °C, activation time of 30 min, CO2 flow rate of 0.05 L/min, irradiation dose of 100 kGy, contact time of 35 min and adsorption dosage of 0.75 g. The optimal DPAC showed a BET surface of 281.33 m2/ g. The removal efficiency was later compared with a commercially available activated carbon which shows a 98.56% phenol removal. The results show that the durian peel could be an effective precursor for making activated carbon for phenol removal, and irradiation can significantly enhance surface activation.

This study aimed to investigate the effect of a coating agent on pork storage. Pork was coated with a coating agent containing sodium carboxymethyl cellulose (CMC) and mandarin peel powder (M). The treatments were divided into control, a 0.1% CMC treatment, and a 0.1% CMC +5% M treatment, and pH, color, 2-thiobarbituric acid reactive substances (TBARS), volatile basic nitrogen (VBN), and the number of viable cell counts were measured. In the case of redness (a), it was found that the reduction over the storage period was less in the 0.1% CMC + 5% M treatment than in the control and the 1% CMC treatment. When stored at 4oC and 25oC, TBARS of pork tended to increase during the storage period, followed by control, 0.1% CMC treatment, and 0.1% CMC + 5% M treatment, indicating that lipid oxidation was most suppressed in pork coated with mandarin peel powder. As a result of measuring the VBN of pork stored at 4oC and 25oC, the 0.1% CMC + 5% M treatment showed lower values than the control and 0.1% CMC treatment. When the film-coated pork was stored at 4oC, the number of viable cell counts in the 0.1% CMC +5% M treatment area was 7.13±0.96 log CFU/g on the 12th day of storage, delaying the growth of viable cell counts for approximately 3 d more than other treatments. Therefore, coating pork with a film containing CMC and mandarin peel powder has been confirmed to delay the increase in the number of viable cell counts while reducing the quality change during pork storage, which is an effective alternative to improving the storage of fresh food as an edible film.

The aim and originality of our current study are to use the original biomass (activated carbon) obtained by functionalizing waste banana peels (commonly found in Turkey) with acid in NaBH4 methanolysis and to examine its contribution to the hydrogen generation rate (HGR). Our study consisted of three stages. In the first stage, the optimum conditions were determined by examining the catalyst under parameters such as different acid types, different carbonization temperatures, and different carbonization times. Thus, based on the maximum HGR value, the optimum conditions were determined as H3PO4, 600 °C, and 40 min. In the second step, the effects of parameters such as acid concentration, NaBH4 concentration, catalyst amount, and temperature on HGR were investigated. As a result of methanolysis experiments (condition: catalyst amount: 100 mg, acid amount: 30%, NaBH4 concentration: 2.5%, temperature: 30 °C, carbonization temperature: 400 °C, and carbonization time: 40 min.), the maximum HGR value, the reaction completion time and activation energy were found as 65,625 mLmin− 1gcat−1, 0.233 min, and 4.56 kJ/mol, respectively. It was observed that the obtained activation energy was lower than that of some catalysts available in the literature. In addition, the structural and morphological examination of the banana peel (catalyst) with high HGR and low activation energy revealed that the acid functionalization process was successfully carried out.

There is an ever growing interest in the development of biochar from a large variety of agrowastes. Herein, the main objective is the conversion of pomegranate peel powder biochar and its post-functionalization by phosphoric acid treatment, followed by arylation organic reaction. The latter was conducted using in situ-generated diazonium salts of 4-aminobenzoic acid ( H2N-C6H4-COOH), sulfanilic acid ( H2N-C6H4-SO3H) and Azure A dye. The effect of diazonium nature and concentration on the arylation process was monitored using thermal gravimetric analysis (TGA) and Raman spectroscopy, scanning electron microscopy (SEM), and X-ray photoelectron spectroscopy (XPS). SEM pictures showed micrometer-sized biochar particles with tubular structure having about 10–20 μm-wide channels. SEM studies have shown that arylation did not affect the morphology upon arylation. The porous structure did not collapse and withstood the arylation organic reaction in acid medium did not collapse upon arylation. TGA and Raman indicated gradual changes in the arylation of biochar at initial concentrations 10– 5, 10– 4 and 10– 3 mol L− 1 of 4-aminobenzoic acid. The detailed Raman spectra peak fittings indicate that the D/G peak intensity ratio leveled off at 3.35 for 4-aminobenzoic acid initial concentration of 10– 4 mol L− 1, and no more change was observed, even at higher aryl group mass loading. This is in line with formation of oligoaryl grafts rather than the grafting of new aryl groups directly to the biochar surface. Interestingly, Azure A diazonium salt induced much lower extent of surface modification, likely due to steric hindrance. To the very best of our knowledge, this is the first report on diazonium modification of agrowaste-derived biochar and opens new avenues for arylated biochar and its applications.

Activated non-graphitizable hard carbon using orange peel with mesoporous structure has been prepared by pyrolyzation at 700, 800, 900 °C using chemical activation method. The activated orange peel-derived hard carbon has been characterized for its mesoporous and disordered structure. TG-DSC gives the information for the changes about sample composition and thermal stability of the materials. Increasing the carbonization temperature for orange peel precursor using NaOH as activating agent, elevates the pore diameter, which thereby facilitating the insertion of Na+. Raman and X-ray diffraction confirms the presence of disordered carbon. The surface morphology of the material was analyzed by scanning eletron microsope and nitrogen ( N2) adsorption and desorption analysis give the morphology, mesopore size (3.374, 3.39 and 4 nm) and surace area (60.164, 58.99 and 54.327 m2/g) of the orange peel-derived hard carbon. Hence, this work strongly evidences that the biomass-derived hard carbon with good porosity and paves way of superior electrochemical performance for emerging sodium ion batteries.

The discharge of dye-containing industrial effluents such as methylene blue (MB) in water bodies has resulted in severe aquatic and human life problems. In addition to this factor, there is the accumulation of banana peel wastes, which can generate ecological damage. Thus, this research purpose a different method from the literature using the banana peel waste (BP) to produce activated carbon (ACBP) by NaOH activation followed by pyrolysis at 400 °C to remove methylene blue (MB). The material was characterized by TGA, XRD, SEM, BET, and FTIR. The influence of dye concentration (10, 25, 50, 100, 250, and 500 mg L−1) was investigated. ACBP presented a well-developed pore structure with a predominance of mesopores and macropores. This morphological structure directly influences the MB removal capacity. The highest efficiency for dye removal was in the MB initial concentration of 25 mg L−1, sorbent of 0.03 g, and contact time of 60 min, which were 99.8%. The adsorption isotherms were well defined by Langmuir, Freundlich, and Temkin isotherm models. The Langmuir model represented the best fit of experimental data for ACBP with a maximum adsorption capacity of 232.5 mg g−1. This adsorbent showed a comparatively high performance to some previous works. So, the banana peel waste is an efficient resource for producing activated carbon and the adsorption of methylene blue.

마에는 다양한 기능성 성분이 함유되어 있어서 식용 및 약용으로 다양하게 이용되고 있다. 특히 allantoin은 대표적인 마의 2차 대사산물로서 의약품 및 기능성 화장품 제조에도 활용되는 고부가가치 산물이다. 본 연구에서는 아미노 결합 정지상 HPLC 컬럼을 이용하여 마의 속과 껍질의 allantoin 함량을 분석하였다. Allantoin 표준용액의 검량 선의 결정계수(R2)값은 0.9999로 높은 직진성을 보였으며, 검출한계(LOD)와 정량한계(LOQ)는 각각 0.0229 mg/mL 및 0.0694 mg/mL로 설정되었다. 마 속과 껍질의 건조중량 기준 allantoin 함량은 각각 3.09±0.02 mg/g, 3.91±0.11 mg/g으로 속보다 껍질에 더 많은 allantoin이 함유되어있음을 확인하였다. 따라서 이러한 결과를 토대로 향후 농업부산물인 마껍질이 새로운 고부가가치 기능성 소재로 활용될 수 있음을 확인하였다.

본 연구에서는 국내 시판되고 있는 진피차 10종을 무작위로 구매하여 외관 및 기본 정보와, 각 티백을 80oC의 열수 100 mL에서 5분간 침출한 용액의 당도, pH, 적정 산도, 환원당 함량, Vitamin C 함량, 총 폴리페놀 함량, 총 플라보노이드 함량을 분석하였다. 진피차 10종은 모두 100% 진피를 사용했으며 첨가물이 들어있지 않았다. 당도와 산도는 진피를 많이 함유한 T10에서 가장 높게 나타났으며 동일한 제조사 제품의 경우 외관상 입자크기가 큰 제품에서 당도값이 높게 나타났다. pH는 일정한 경향이 나타나지 않았으며 이는 원료 및 제조공정의 차이로 인한 것으로 생각된다. 환원당 함량과 Vitamic C 함량은 진피 함유량이 증가할수록 함량이 높아지는 경향을 나타냈다. 총 폴리페놀 함량은 8.69-33.42 mg GAE/100 mL의 범위에서 진피 함유량이 높을수록 총 폴리페놀 함량이 높게 나타났다. 총 플라보노이드 함량은 T10에서 가장 높은 값을 보였고, T1이 가장 낮은 값을 나타냈으며 총 폴리페놀 함량 결과와 유사한 경향 을 보였다. 본 연구에서 진피차는 중량, 입자크기에 따라 이화학 특성이 달라진다는 것을 확인하였으며 이외에도 원료나 제조공정에 따른 차이가 있을 것으로 판단된다. 이를 바탕으로 진피차의 품질향상 및 신제품 개발 시기초정보로 활용하는 데 도움이 될 것으로 생각된다. 본 연구는 시판 진피차를 시료로 이용했기 때문에 명시된 정보 이외에 품질 특성에 관여하는 건조방법, 귤 품종, 재배지역에 관한 정보는 알 수 없었다. 따라서 이러한 조건에 따른 진피차의 품질특성에 관한 추가적인 연구가 필요할 것으로 생각된다.

In this study, we report a controlled one-pot green synthesis of multiwalled carbon nanotubes (MWCNTs) via pyrolysis of sustainable agriculture waste (chickpea peel) at 400 °C in aqueous medium. These MWCNTs demonstrated 7.0 nm diameter, 0.28 nm graphitic spacing with carbonyl, hydroxyl, and carboxylic acid functionality. The D band (presence of sp3 defects) and G band ( E2g mode of graphite) at 1350 cm−1 and 1580 cm−1 originated in Raman spectrum, respectively. The prepared MWCNTs showed blue fluorescence with 10% fluorescence quantum yield in aqueous medium. The MWCNTs showed triple exponential decay characteristics with an average fluorescence lifetime of 4.7 ns. The synthesized MWCNTs revealed a consistent fluorescence in the cytoplasm of 22RV1 human prostate carcinoma cell line without exerting any sign of cytotoxicity. The MWCNTs also exhibited remarkable cytocompatibility in human immortalized prostate epithelial RWPE1 cells.

Salacca peel-based porous carbon (SPPC) with high surface area (1945 m2 g−1) and large specific pore volume (1.68 cm3 g−1) was prepared by pre-carbonization and K2CO3 activation method. Based on the TGA results, it can be estimated that up to 70 wt% of sulfur-active materials could be infiltrated into the pores of SPPC to form SPPC/S composite cathode for LiS battery. The porous structure of SPPC could act as a buffer layer against volume expansion and minimize the shuttle effect due to the penetration of intermediate polysulfides during cycle tests. Optimization on sulfur loading (50, 60 and 70 wt%) in SPPCC/S composite was also investigated. It was found that the SPPC/S composites with 60 wt% of sulfur loading had the best electrochemical performances. With 60 wt% of sulfur loading, SPPC/S composite electrodes showed excellent electrochemical performances in terms of high initial specific discharge capacity of 1006 mAh g− 1 at 0.5 C and capacity retention of 71% until the 100th cycle. For both cases of low and high sulfur loading, they caused much worse electrochemical performances. Based on the experimental results, it can be concluded that porous carbons derived from the salacca peel were promising materials for sulfur loading in LiS battery.

The carboxylated multi-walled carbon nanotubes (MWCNTs–COOH) were used as adsorbent for the separation of flavonoids (naringin and rutin) from bitter orange peel. The influence of the parameters such as, pH values, contact time, and desorption conditions was investigated. The samples were characterized by Fourier transform infrared spectroscopy, thermogravimetric analysis, derivative thermogravimetric, scanning electron microscopy, UV–Vis spectroscopy, and high-performance liquid chromatography. After separation and desorption process, the eluent was injected for chromatography analysis. Under the optimal conditions, experimental results showed that the extraction efficiency of rutin was higher than naringin and other compounds. Moreover, the desorption percentage of flavonoids was calculated 83.6% after four cycles. This research confirmed that this method for separation of flavonoids is simple and less cost. In addition, the separated flavonoids can be used as antioxidant for the future applications.

The objective of this study was to reduce the waste rate of onion peel, which has excellent functionalities, and to promote its industrial utilization. The methodology involved preparing beef jerkies using liquid seasonings with 0% (OPE0), 50% (OPE50) and 100% (OPE100) onion peel extract (OPE) of domestically produced onion, respectively; and assessing their antioxidant activities and quality characteristics. As the amount of added OPE increased, the contents of crude protein and crude ash increased, while those of crude fat decreased. As for color values, increase in the amount of added OPE led to increase in L value and b value, but decrease in a value. The measurement of mechanical texture showed that hardness and cohesiveness decreased as the amount of added OPE increased. TBARS (thiobarbituric acid reactive substance) content decreased as the amount of added OPE increased. And the amount of added OPE increased, all the antioxidant activity of beef jerky increased. Acceptability test showed the highest preference for OPE50 with regard to flavor, taste texture and overall acceptability. Quantitative descriptive analysis (QDA) showed that increase in the amount of added OPE led to increase in meat color, salty taste, sweet taste, meat flavor and chewiness and decrease in off-flavor. According to principal component analysis (PCA), OPE50 and OPE100 had high levels of the sensory attributes that increase preference-such as meat color, salty taste, sweet taste, meat flavor and chewiness. Based on such results, it was established that 50% is the optimal mixing ratio of OPE for preparing a beef jerky of high preference that also has excellent quality characteristics and antioxidant activity.

치자 껍질의 phytic acid 함량과 CM (chloroform:methanol, 2:1, v/v), n-부탄올 및 70% 에탄올을 사용한 추출물의 용매(3가지) 별 총 페놀 함량 및 항산화 활성 능력 등을 통하여 치자 껍질의 효용 가치를 검토한 결과, phytic acid 함량은 4.966±0.996 mg PAE/g DW (dry weight)로 나타났으며, 용매 별 생리 활성은 농도(0.2, 0.4, 0.6 mg/mL)가 높아질수록 유의적으로 증가하였으며(p<0.05), 양성대조군으로 사용된 ascorbic acid, BHA, trolox 보다는 각 농도에서 낮은 활성이 관찰되었다. 치자 껍질의 총 페놀 함량은 CM, n-부탄올, 70% 에탄올 추출물 순으로 CM 추출물에서 39.74±0.15 mg CAE/g으로 가장 높았으며, nitric oxide (NO) 라디칼 소거능과 지질과산화 저해능은 용매 별로 CM > 70% 에탄올 > n-부탄올, nitrite (NO2) 소거능은 n-부탄올 > CM > 70% 에탄올, β-carotene 탈색 저해능과 환원력은 CM > n-부탄올 > 70% 에탄올 순의 활성이 나타났다. 이상의 결과, 치자 껍질의 용매 별 총 페놀 함량 순과 항산화력, 환원력은 일치 하였으며, 질소산화물 소거능과 지질과산화 저해능 분석에서는 일치하지 않은 것으로 확인되었다. 이는 질소산화물 소거능과 지질과산화 저해능은 페놀 성분 보다 다른 생리활성물질이 더 큰 영향을 주는 것으로 추정된다. 이에, 치자 껍질은 질소산화물 소거능, 항산화능 및 지질과산화 저해능 등이 우수한 것으로 나타나 기능성 식품 소재로서의 가치가 있는 것으로 판단된다.

Citrus fruit is important source of flavonoids, mainly flavanones which are narirutin and hesperidin. Those citrus flavonoids have been found to have health-related properties including antioxidant, anticancer, and anti-inflammatory. The main purpose of this study was to verify that the extraction of narirutin and hesperidin from Citrus peel can be more effective by combining pulsed electric field (PEF) pre-treatment and subcritical water extraction (SWE). Citrus unshiu peels were treated with PEF under conditions of electric field strength (3 kV/cm) and times (1 and 2 min). Subsequent SWE was conducted by using a Dionex Accelerated Solvent Extractor (ASE, Model 350) at extraction temperature 170°C for 10 min. The total flavonoids content was measured by using the aluminum chloride colorimetric method and the antioxidant capacity was analyzed by the Ferric reducing antioxidant power (FRAP) assay using spectrophotometer. The concentrations of narirutin and hesperidin were increased as PEF pre-treatment time increased. The highest concentrations of narirutin and hesperidin were 13.41 mg narirutin/g dry citrus peel and 141.16 mg hesperidin/g dry citrus peel at PEF pre-treatment condition of 3 kV/cm and 2 min. The total flavonoids contents of the extracts increased 105.2% and 123.1% for citrus peel PEF treated at 1 and 2 min, respectively. In addition, compared to the untreated sample, PEF pre-treatments of 1 and 2 min increased the antioxidant capacity of the extracts 109.2% and 160.8%, respectively. Therefore, the results demonstrate the potential of PEF pre-treatment to improve the SWE of flavonoids from citrus unshiu peel.

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°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.