K.O. Kim

Textural Properties of Gelling System of Low‐Methoxy Pectins Produced by Demethoxylating Reaction of Pectin Methyl Esterase

After deesterification of commercial pectins with a pectin methyl esterase (PME), their gelling properties were characterized using instrumental texture analysis. The final degree of esterification (DE) of the high- and low-methoxy pectins reached approximately 6% after the PME treatment, while deesterification of low-methoxy amidated pectin stopped at 18% DE. Furthermore, DE of high-methoxy pectin was tailored to be 40%, which is equivalent to the DE of commercial low-methoxy pectin. As a result, significant changes in molecular weight (Mw) distribution were observed in the PME-treated pectins. The texture profile analysis showed that PME modification drastically increased hardness, gumminess, and chewiness, while decreasing cohesiveness and adhesiveness of the pectin gels (P < 0.05). The pectin gel with relatively high peak molecular weight (Mp, 3.5 x 10(5)) and low DE (6), which was produced from high-methoxy pectin, exhibited the greatest hardness, gumminess, chewiness, and resilience. The hardness of low-methoxy amidated pectin increased over 300% after PME deesterification, suggesting that the effects of amide substitution could be reinforced when DE is even lower. The partial least square regression analysis indicated that the Mw and DE of the pectin molecule are the most crucial factors for hardness, chewiness, gumminess, and resilience of gel matrix.

Sensory characteristics and consumer acceptability of decaffeinated green teas.

Green tea has been widely consumed for its mild flavors and its health benefits, yet caffeine in green tea has been a limitation for those who want to avoid it. The limitation brought increase in need for decaffeinated products in the green tea market. Most of the conventional decaffeination techniques applied in food use organic solvents. However, supercritical carbon dioxide fluid extraction (SC-CO2) method is gaining its intension as one of the future decaffeination methods that overcomes the problems of conventional methods. The purpose of this study was to identify sensory characteristics of decaffeinated green teas applied with SC-CO2 method and to observe the relationship with consumer acceptability to elucidate the potentiality of applying SC-CO2 technique in decaffeinated green tea market. Descriptive analysis was performed on 8 samples: green teas containing 4 caffeine levels (10%, 35%, 60%, and 100%) infused at 2 infusing periods (1 or 2 min). It was found that the SC-CO2 process not only reduced caffeine but also decreased some important features of original tea flavors. Two groups were recruited for consumer acceptability test: one (GP I, N = 52), consuming all types of green teas including hot/cold canned teas; and the other (GP II, N = 40), only consuming the loose type. While GP II liked original green tea the most, GP I liked highly decaffeinated green teas. Although the SC-CO2 method had limitations of losing complex flavors of green teas, it appeared to have future potential in the decaffeinated green tea market within or without the addition of desirable flavors.

Physicochemical Properties of Partially Oxidized Corn Starch from Bromide-Free TEMPO-Mediated Reaction

This study was conducted to determine the optimal temperature and time for the regiospecific oxidation of primary alcohol groups in corn starch with 2,2,6,6-tetramethyl-1-piperidinyl oxoammonium ion (TEMPO) and sodium hyphochlorite (NaOCl). The study also elucidated the molecular structure of fully oxidized corn starch (FOCS) prepared at optimum temperature and physicochemical properties of the partially (10%, 20%, and 30%) oxidized corn starches (POCS). The reaction time rapidly decreased up to 30 degrees C, and then gradually decreased. Selectivity, yield, and viscosity were drastically reduced at temperatures higher than 35 to 40 degrees C. Optimal oxidation temperature for the production of FOCS was determined as 35 degrees C. Regiospecific oxidation of the primary alcohol group without oxidation of the secondary alcohol group was confirmed in (13)C-NMR and IR spectra. Water-binding capacity, swelling power, solubility power, and transmittance of POCS increased as the degree of oxidation increased. Hardness, gumminess, and chewiness of corn starch gel containing POCS were not significantly different from those of native corn starch gel at 1-d storage, but the values of the starch gel containing POCS were smaller than those of the native starch gel after 1-d storage. However, springiness and cohesiveness did not differ significantly among the samples regardless of storage time.

Β-carotene inhibits neuroblastoma tumorigenesis by regulating cell differentiation and cancer cell stemness.

Neuroblastoma (NB) is the most common extracranial solid cancer in young children and malignant NB cells have been shown to possess cancer stem cell (CSC) characteristics. Thus, the successful elimination of CSCs represents a strategy for developing an effective preventive and chemotherapeutic agent. CSCs are characterized by differentiation and tumorigenicity. β-Carotene (BC) has been associated with many anticancer mechanisms, although the efficacy of BC on CSCs remains unclear. In the present study, the effects of BC on tumor cell differentiation and tumorigenicity was investigated using a xenograft model. Mice were pretreated with BC for 21 days, then received a subcutaneous injection of SK-N-BE(2)C cells. Both tumor incidence and tumor growth were significantly inhibited for mice that received BC supplementation compared to the control group. Treatment with BC has also been shown to induce tumor cell differentiation by up-regulating differentiation markers, such as vimentin, peripherin, and neurofilament. Conversely, BC treatment has been shown to significantly suppress tumor stemness by down-regulating CSC markers such as Oct 3/4 and DLK1. BC treatment also significantly down-regulated HIF1-α expression and its downstream target, vascular endothelial growth factor (VEGF). Taken together, these results suggest that BC is a potential chemotherapeutic reagent for the treatment of NB, and mediates this effect by regulating the differentiation and stemness of CSCs, respectively.

Sasa quelpaertensis leaf extract suppresses dextran sulfate sodium–induced colitis in mice by inhibiting the proinflammatory mediators and mitogen-activated protein kinase phosphorylation

Sasa quelpaertensis leaves exert anti-inflammatory and anticarcinogenic effects, although it remains unclear whether these leaves can suppress inflammation-related intestinal diseases. This study hypothesized that Sasa quelpaertensis leaf extract (SQE) exerts a protective effect against inflammation in a dextran sulfate sodium (DSS)-induced colitis mouse model. Therefore, colon tissues of DSS-induced colitis mice that were treated with SQE were assayed for levels of proinflammatory markers, mitogen-activated protein kinase signaling, and activation of nuclear factor κB. For this purpose, mice were pretreated with SQE (100 mg/kg or 300 mg/kg body weight) by gavage for a 2-week period. Mice then received either SQE or sulfasalazine (100 mg/kg body weight) with 2.5% DSS in drinking water for 7 days twice daily and 7 days of tap water ad libitum between DSS treatment. Treatment with SQE was found to attenuate the severity of DSS-induced colitis, as assessed by disease activity index scores, shrinkage of colon length, and histopathologic changes. SQE reduced DSS-induced proliferation in distal colon tissues. It also significantly suppressed levels of tumor necrosis factor-α in serum and colon tissues, nitric oxide synthase, cyclooxygenase, and levels of phosphorylated c-Jun N-terminal kinases, p38, extracellular-signal-regulated kinases 1/2, and IκBα in colon tissues. To our knowledge, this is the first study to demonstrate that SQE supplementation can exert an anti-inflammatory effect on experimental chronic colitis.

Sensory characteristics and consumer acceptability of red ginseng extracts produced with different processing methods.

UNLABELLED The aims of this study were: to develop objective and effective sample preparation and presentation procedures for the sensory analysis of red ginseng extracts (RGE); to identify their sensory attributes in relation with the consumer acceptability of RGEs produced with different processing techniques. The samples included 7 different types of RGE, among which 2 samples were of commercial products and the other samples were specially prepared for the study. The samples differed in processing methods (traditional method, high-hydrostatic pressure [HHP], and fermentation) and extraction solvents (ethanol, water). For the descriptive analysis, 7 trained panelists developed and evaluated 30 attributes. Principal component analysis was conducted to summarize the relationships between the sensory attributes and to get a representation of the samples according to those attributes. Consumers evaluated the appearance and flavor acceptability of the extracts. Hierarchical cluster analysis was conducted on consumer acceptability of flavor. The results showed that the clear differences among the RGEs in terms of sensory perceptions were explained by the processing methods. Consumers were segmented into 3 distinct groups in terms of preference: a consumer cluster that likes the RGEs produced with HHP or fermentation, a cluster that likes a product with strong ginseng flavor, and a cluster that likes a RGE with sweet taste and jujube flavor. These 3 clusters differed somewhat in their consumption frequency and purchase factors, also. PRACTICAL APPLICATION The red ginseng extract (RGE) market is rapidly growing due to the consumer awareness of its superior health-promoting effects. However, little attention has been given to sensory properties that are a critical factor in determining quality and consumer preference. The results of this study will be helpful for researchers and manufacturers to understand the sensory characteristics of RGEs and to detect the driving factors of consumer acceptability. Also, the sample preparation and presentation procedures developed in this experiment will be used effectively in academia and industries to examine sensory characteristics of RGE products.

Combination of Sasa quelpaertensis Nakai Leaf Extract and Cisplatin Suppresses the Cancer Stemness and Invasion of Human Lung Cancer Cells

Lung cancer is the leading cause of cancer death worldwide, and most chemotherapeutic drugs have limited success in treating this disease. Furthermore, some drugs show undesirable side effects due to the enrichment of cancer stem cells (CSCs) that are present, leading to resistance to conventional chemotherapy and tumor relapse. CSCs possess self-renewal characteristics, aggressive tumor initiating activity, and ability to facilitate tumor metastasis. Therefore, development of nontoxic agents that can potentiate chemotherapy and eliminate CSCs would be highly desirable. In the present study, we investigated whether Sasa quelpaertensis leaf extracts (SQE) and cisplatin (CIS), individually or in combination, would exert anti-CSC and antimetastatic effect in H1299 and A549 human lung cancer cells. Following these treatments, cell growth, phosphorylation of phosphoinositide-3 kinase, and activation of the mammalian target of rapamycin were inhibited. Decreased serial sphere formation, clonogenicity, and expression of major stem cell markers, such as CD44 and SOX-2, in CD44+ cancer stem cells were also observed. In addition, inhibition of cell migration and invasion in both cell lines as well as inhibition of matrix metalloproteinase-2 activity and expression were detected. Importantly, the anticancer stemness and antimetastasis effects in each of these assays were greater for the combined treatment with SQE and CIS than with each treatment individually. In conclusion, the data suggest that SQE alone, or in combination with CIS, represents a promising therapeutic strategy for eliminating cancer stemness and cell invasion potential of CSCs, thereby treating and preventing metastatic lung cancer cells.