• Nutrition Research and Practice
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• v.8 no.1
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• pp.33-39
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• 2014

Obesity occurs when a person's calorie intake exceeds the amount of energy burns, which may lead to pathologic growth of adipocytes and the accumulation of fat in the tissues. In this study, the effect and mechanism of pear pomace extracts on 3T3-L1 adipocyte differentiation and apoptosis of mature adipocytes were investigated. The effects of pear pomace extract on cell viability and the anti-adipogenic and proapoptotic effects were investigated via MTT assay, Oil red O staining, western blot analysis and apoptosis assay. 3T3-L1 preadipocytes were stimulated with DMEM containing 10% FBS, 0.5 mM 3-isobutyl-1-methylxanthine (IBMX), $5{\mu}g/ml$ insulin and $1{\mu}M$ dexamethasone for differentiation to adipocytes. 3T3-L1 cells were cultured with PBS or water extract of pear pomace. Water extract of pear pomace effectively inhibited lipid accumulations and expressions of PPAR-${\gamma}$ and $C/EBP{\alpha}$ in 3T3-L1 cells. It also increased expression of p-AMPK and decreased the expression of SREBP-1c and FAS in 3T3-L1 cells. The induction of apoptosis was observed in 3T3-L1 cells treated with pear pomace. These results indicate that pear pomace water extract inhibits adipogenesis and induces apoptosis of adipocytes and thus can be used as a potential therapeutic substance as part of prevention or treatment strategy for obesity.

• Journal of Microbiology and Biotechnology
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• v.27 no.4
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• pp.856-867
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• 2017

Supplement of dietary fibers (DF) is regarded as one of the most effective way to prevent and relieve chronic diseases caused by long-term intake of a high-fat diet in the current society. The health benefits of soluble dietary fibers (SDF) have been widely researched and applied, whereas the insoluble dietary fibers (IDF), which represent a higher proportion in plant food, were mistakenly thought to have effects only in fecal bulking. In this article, we proved the anti-obesity and glucose homeostasis improvement effects of IDF from pear pomace at first, and then the mechanisms responsible for these effects were analyzed. The preliminary study by real-time PCR and ELISA showed that this kind of IDF caused more changes in the gut microbiota compared with in satiety hormone or in hepatic metabolism. Further analysis of the gut microbiota by high-throughput amplicon sequencing showed IDF from pear pomace obviously improved the structure of the gut microbiota. Specifically, it promoted the growth of Bacteroidetes and inhibited the growth of Firmicutes. These results are coincident with previous hypothesis that the ratio of Bacteroidetes/Firmicutes is negatively related with obesity. In conclusion, our results demonstrated IDF from pear pomace could prevent high-fat diet-induced obesity in rats mainly by improving the structure of the gut microbiota.

• Nutrition Research and Practice
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• v.16 no.5
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• pp.577-588
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• 2022

BACKGROUND/OBJECTIVES: Poorly regulated inflammation is believed to be the most predominant factor that can result in a wide scope of diseases including atopic dermatitis (AD). Despite many studies on the effect of pear pomace in obesity-related disorders including dysregulated gut microbiota, the protective effect of pear pomace in AD is still unknown. This study aimed to evaluate the effect of pear pomace ethanol extract (PPE) on AD by inhibiting inflammation. MATERIALS/METHODS: In the in vivo experiment, 2, 4-dinitrochlorobenzene (DNCB) was applied to NC/Nga mice to induce AD-like skin lesions. After the induction, PPE was administered daily by oral gavage for 4 weeks. The clinical severity score, serum IgE levels, spleen weight, histological changes in dorsal skin, and inflammation-related proteins were measured. In the cell study, RAW 264.7 cells were pretreated with PPE before stimulation with lipopolysaccharide (LPS). Nitrite oxide (NO) production and nuclear factor kappa B (NF-𝛋B) protein expression were detected. RESULTS: Compared to the AD control (AD-C) group, IgE levels were dramatically decreased via PPE treatment. PPE significantly reduced scratching behavior, improved skin symptoms, and decreased ear thickness compared to the AD-C group. In addition, PPE inhibited the DNCB-induced expression of inducible nitrite oxide synthase (iNOS), the receptor for advanced glycation end products, extracellular signal-regulated kinase (ERK) 1/2, and NF-𝛋B. PPE inhibited the LPS-induced overproduction of NO and the enhanced expression of iNOS and cyclooxygenase-2. Moreover, the phosphorylation of ERK1/2 and NF-𝛋B in RAW 264.7 cells was suppressed by PPE. CONCLUSIONS: These results suggest that PPE could be explored as a therapeutic agent to prevent AD.

• Korean Journal of Food Science and Technology
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• v.31 no.4
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• pp.971-976
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• 1999

Exo-polygalacturonase (EPG) from Rhizopus sp. was applied to the extraction of pectin from pear pomace because EPG produces pectin by solubilizing protopectin. The content of total galacturonic acid in water-alcohol insoluble pectin (WAIP) was determined as 34.6%. Pear pomace was solubilized by using EPG, with regarding reaction pH, temperature, time and ratio of enzyme to substrate in order to find optimum condition. While the yield by an acidic treatment was 6.2%, the maximum yield by an enzymatic treatment was 23.4% under the extraction condition of pH 7.8, $60^{\circ}C$, 36 hr and 1/10 of enzyme/substrate. At this condition, the purity and methoxyl content of enzyme-extracted pectin were, respectively, 34.7% and 0.7%, while those of acid-extracted pectin were, respectively, 71.1% and 5.0%. Meanwhile, the average molecular weight of pectin extracted by the enzymatic method was $2.5{\times}10^{3}$ while that of acid-solubilized pectin was $8.4{\times}10^{3}$.

• Journal of the Korean Society of Food Science and Nutrition
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• v.44 no.11
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• pp.1682-1686
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• 2015

This study was conducted to establish an HPLC analysis method for determination of marker compounds as part of materials standardization for development of health functional food materials from pear pomace. The quantitative determination method of caffeic acid and chlorogenic acid as marker compounds of pear pomace extract (PPE) was optimized by HPLC analysis using a C18 column ($5{\times}250mm$, $5{\mu}m$) with a 0.2% elution gradient of acetic acid and methanol as the mobile phase at a flow rate of 0.8 mL/min and detection wavelength of 330 nm. The HPLC/UV method was applied successfully to the quantification of marker compounds in PPE after validation of the method with linearity, accuracy, and precision. The method showed high linearity of the calibration curve with a coefficient of correlation ($R^2$) of 0.9999, and limit of detection and limit of quantification were $1.14{\mu}g/mL$ (caffeic acid) and $1.61{\mu}g/mL$ (chlorogenic acid) as well as $4.9{\mu}g/mL$ (caffeic acid) and $4.9{\mu}g/mL$ (chlorogenic acid), respectively. Relative standard deviation values from intra- and inter-day precision were less than 3.1% (caffeic acid) and 4.0% (chlorogenic acid), respectively. Recovery rates of caffeic acid and chlorogenic acid at 12.5, 25, and $50{\mu}g/mL$ were 93.66~106.32% and 97.33~105.68%, respectively. An optimized method for extraction of caffeic acid and chlorogenic acid in PPE was established through diverse extraction conditions, and the validation indicated that the method is very useful for evaluation of marker compounds in PPE to develop a health functional food material.

• Nutrition Research and Practice
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• v.11 no.3
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• pp.198-205
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• 2017

BACKGROUND/OBJECTIVES: The anti-diabetic activity of pear through inhibition of ${\alpha}-glucosidase$ has been demonstrated. However, little has been reported about the effect of pear on insulin signaling pathway in obesity. The aims of this study are to establish pear pomace 50% ethanol extract (PPE)-induced improvement of insulin sensitivity and characterize its action mechanism in 3T3-L1 cells and high-fat diet (HFD)-fed C57BL/6 mice. MATERIALS/METHODS: Lipid accumulation, monocyte chemoattractant protein-1 (MCP-1) secretion and glucose uptake were measure in 3T3-L1 cells. Mice were fed HFD (60% kcal from fat) and orally ingested PPE once daily for 8 weeks and body weight, homeostasis model assessment of insulin resistance (HOMA-IR), and serum lipids were measured. The expression of proteins involved in insulin signaling pathway was evaluated by western blot assay in 3T3-L1 cells and adipose tissue of mice. RESULTS: In 3T3-L1 cells, without affecting cell viability and lipid accumulation, PPE inhibited MCP-1 secretion, improved glucose uptake, and increased protein expression of phosphorylated insulin receptor substrate 1 [p-IRS-1, ($Tyr^{632})$)], p-Akt, and glucose transporter type 4 (GLUT4). Additionally, in HFD-fed mice, PPE reduced body weight, HOMA-IR, and serum lipids including triglyceride and LDL-cholesterol. Furthermore, in adipose tissue, PPE up-regulated GLUT4 expression and expression ratio of p-IRS-1 ($Tyr^{632})/IRS$, whereas, down-regulated p-IRS-1 ($Ser^{307})/IRS$. CONCLUSIONS: Our results collectively show that PPE improves glucose uptake in 3T3-L1 cells and insulin sensitivity in mice fed a HFD through stimulation of the insulin signaling pathway. Furthermore, PPE-induced improvement of insulin sensitivity was not accompanied with lipid accumulation.

• Korean Journal of Food Science and Technology
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• v.51 no.3
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• pp.286-294
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• 2019

The purpose of this study was to investigate the possibility of enhancing the functional compounds in apple and pear pomace (APP) by fermentation with mycelia from the mushroom Lentinula edodes. A 30% (w/v) APP with added rice bran and Biji was fermented with L. edodes at $24^{\circ}C$ and 80% humidity. The cellulase and pectinase activities in the fermented APP (FAPP) were higher than those in the non-fermented control. In addition, the physiological activities of the FAPP, including DPPH, ABTS radical scavenging, and SOD-like activity, as well as the total polyphenol and ${\beta}-glucan$ contents were higher than those in the control. FAPP treatment significantly reduced LPS-induced nitric oxide (NO) levels in Raw 264.7 cell. Therefore, FAPP treatment was considered to more effectively suppress cell injury caused by inflammatory cytokines through inhibition of LPS-induced NO production. These results suggest that the levels of functional components in APP can be increased by fermentation with this mushroom mycelium. However, further studies are needed before it can be used as a functional material.

• Food Science of Animal Resources
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• v.30 no.3
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• pp.466-471
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• 2010

This study investigated the effects of dietary supplementation of fermented apple pomace (FAP), fermented pear pomace (FPP), fermented orange pomace (FOP), and fermented Angelica keiskei Koidz pomace (FAKP) on performance, shelf life, fatty acid composition and cholesterol in broiler chickens. A total of 600, 1-day-old male broiler chicks (Cobb strain) were randomly divided into six groups with four replicates of 30 birds each. There were five treatment groups: control (C), FAP (1.0%, T1), FPP (1.0%, T2), FOP (1.0%, T3), and FAKP (1.0%, T4). The body weight of the broiler chickens fed FAP diet was higher (1,758 g) than the other treatments. There was no difference in the thiobarbituric acid reactive substances (TBARS) in chicken meat between all groups at days 1, 3, and 5 of storage, while the FAP-supplemented group displayed lower TBARS values at day 7. There was no significant difference in fatty acid composition between the groups but the cholesterol content of chicken meat was lower than the control groups. These results suggest the possibility that FAP could be used as a functional feed to improvement the quality performance of broiler chickens.

• Journal of Animal Science and Technology
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• v.45 no.2
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• pp.251-264
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• 2003

This study was conducted to make on-site survey on the output pattern and utilization situation of 19 by-products selected, to evaluate their nutritional characteristics, to find out a reliable index with which digestion of by-products can be predicted on the basis of chemical compositions analyzed and to diagnose the risk of using book values in the absence of the actual values analyzed for diet formulation. Production and utilization situations of by-products were quite various. Nutritionally, fruit processing by-products such as apple pomace (AP), pear pomace (PP), grape pomace (GP), and persimmon peel (PSP), and bakery by-products (BB) were classified as energy feeds. Soybean curd meal (SCM), animal by- products such as blood (BD), feather meal (FM) and poultry by-products (PB), and activated milk processing sludge (AMS) were classified as protein feeds. Soy hulls (SH), spent mushroom compost (SMC), barley malt hulls (BMH), waste paper (WP) and broiler litter (BL) were classified as roughage. Rumen contents (RC) and restaurant food waste (FW) were nutritionally analogous to complete diets for cattle and swine, respectively. Compared to soybean meal (SBM), BD and FM contained high (P<0.05) levels of amino acids and barley malt sprouts (BMS), AMS and FW contained low (P<0.05) levels of amino acids. Enzymatic (pepsin) digestibilities of proteinaceous feeds ranged between 99 and 66%. In vitro DM digestibility was high (P<0.05) in the order of FW, BB, AP, SH, PP, PSP, BMH, BMS, SCM, GP, RC, PB, BL, WP, SMC, AMS, FM and BD. In vitro DM digestibility had the highest correlation (r=0.68) with nonfibrous carbohydrate among chemical components. Differences between analyzed values of chemical components and book values were considerable. Caution is required in using book values when large amount of by-products are used in diets.