Chemical conversion of ginsenosides in puffed red ginseng

The effects of puffing process on chemical conversion of ginsenosides, extraction yields and crude saponin contents in red ginseng were investigated. To reach a maximum extraction yield, puffed red ginseng took only 8 h, while non-puffed red ginseng required at least 20 h showing extraction yields of 45.7 g solid extract/100 g sample and 44.5 g solid extract/100 g sample, respectively. Extraction yield increased slightly with increasing puffing pressure. Puffed red ginseng showed higher crude saponin contents (201.0-219.0 mg/g extract) than non-puffed one (161.7-189.0 mg/g extract). As the puffing pressure increased, minor ginsenosides (Rg3, F2, Rk1 and Rg5) increased but the contents of major ginsenosides (Rb1, Rb2, Rc, Rd, Re and Rg1) decreased. These results indicated that a puffing process may provide an effective method to reduce the extraction time, improve the extraction yield and increase the crude saponin content of red ginseng.     

Steamed ginger (Zingiber officinale): Changed chemical profile and increased anticancer potential

Ginger, from the rhizome of Zingiber officinale Rosco (Zingiberaceae), is a common condiment for foods and beverages. In this work, we tested a hypothesis that a steaming process affects the chemical profile and anticancer potential of ginger. An HPLC method with TOF/MS and DAD was developed to analyse the chemical constituents in ginger. The antiproliferative effect of fresh, dried and steamed gingers was evaluated using human Hela cancer cells. The results showed that the antiproliferative effect of steamed ginger at 120 °C for 4 h was approximately 1.5- and 2-fold higher than that of dried and fresh ginger, respectively. Twenty-two components were characterised in the steamed ginger. The decreased concentration of gingerols and increased levels of shogaols contributed to the improved anticancer potential of the steamed ginger. This study elucidated the relationship of the heating process with the constituents and anticancer activity, and developed an optimised processed ginger extract for chemoprevention.     

Standardization of ginseng processing for maximizing the phytonutrients of ginseng

This study was designed to optimize the process conditions, such as steaming, drying, and extracting, for obtaining the maximum content of prosapogenin (Rg3, Rg2, Rh1, and Rh2) from red ginseng, which has antitumor and anti-cancer properties. The steaming process was performed in an autoclave and the drying and extracting processes were done in dryer and heat extractor, respectively, and content of each prosapogenin was analyzed by HPLC. In the steaming process, prosapogenin values did not show any significant increase at 80 or 90°C, but tended to increase sharply as the steaming period became longer at 100°C, and the maximum value was obtained at 100°C with 6 h of steaming without any significant difference between local Gyeonggi areas. Drying red ginseng at 70°C for 24 h was the optimal condition to enhance prosapogenin extraction without affecting the quality. Maximal crude saponin and prosapogenin contents were obtained using 70% ethanol as the solvent at 70°C in the extracting process. Using these standardization processes such as steaming, drying, and extraction, maximum prosapogenin values could be obtained at ginseng factories.

     

Steam radish sprout (Raphanus sativus L.): active substances,antioxidant activities and non-targeted metabolomics analysis

Various active substances, antioxidant activities and primary differential metabolite profiles were investigated to assess the nutritional quality of radish sprouts steamed for 0–300 s. The levels of flavonoids, total phenolic content and isothiocyanate in radish sprouts decreased with increased steaming time, and DPPH radical scavenging activity levels and superoxide dismutase levels also exhibited a downward trend (P < 0.05). By contrast, total phenolic acid, ferric-reducing antioxidant power and reducing power levels exhibited significant increases in the early short-term steaming process (P < 0.05). Steaming for 30 s promoted the accumulation of vitamin B₂, whereas, steaming for 300 s promoted the accumulation of phospholipids and myristic acid to a greater extent than steaming for 30 s. Overall, there was a partial non-decreased nutritional indicator in short-term steaming of radish sprouts, and a longer steaming time positively affected the differential metabolites.     

Ginsenoside Composition and Antiproliferative Activities of Explosively Puffed Ginseng (Panax ginseng C.A. Meyer)

ABSTRACT: The puffing process was evaluated as an alternative to the steaming process for producing a biologically more active ginseng product, like red ginseng, from raw ginseng. A puffing treatment of dried raw ginseng roots induced an overall increase in crude saponin content. As puffing pressure increased, the content of ginsenoside Re, Rg1, Rb1, Rc, and Rb2 decreased, while ginsenoside Rg3 increased significantly as compared to raw ginseng. The content of ginsenoside Rg3 in puffed ginseng at a pressure of 490 kPa was similar to that of red ginseng. Cancer cell lines (HeLa, MCF-7, and HepG2) showed that antiproliferative effects of saponin extract of puffed ginseng increased with an increase in puffing pressure. Ginseng explosively puffed at 490 kPa had similar saponin constituents and antiproliferative effects as those of red ginseng. Practical Application: The puffing process could provide an alternative mean to produce functional ginseng products, along with a reduction in processing time as compared to traditional red ginseng processing by steam.     

β-Glycosidase-assisted bioconversion of ginsenosides in purified crude saponin and extracts from red ginseng (Panax ginseng C. A. Meyer)

Major ginsenosides in ginseng (Panax ginseng) and its products are highly glycosylated, hence poorly absorbed in the gastrointestinal tract. β-Glycosidase-assisted deglycosylation of pure ginsenosides was peformed to study bioconversion mechanisms. Ginsenoside standard compounds, crude saponin, and red ginseng extracts were incubated with β-glycosidase (0.05% w/v, 55°C). β-Glycosidase has a broad specificity for β-glycosidic bonds, hydrolyzing the β-(1→6), α-(1→6), and α-(1→2) glycosidic linkages. The final metabolite of protopanaxadiol ginsenosides was Rg3 while the metabolite of protopanaxatriol ginsenosides was Rh1. β-Glycosidase treatment of red ginseng extracts resulted in a decrease in the amounts of Rb1, Rc, Re, and Rg2 after 24 h, whereas levels of the less glycosylated Rd, Rb1, Rg, Rg3, Rg1, and Rh1 forms increased. When crude saponin was incubated with β-glycosidase for 24 h, levels of Rb1, Rc, Re, and Rg1 decreased while levels of Rd, Rg3, and Rh1 increased as deglycosylated ginsenosides.     

Effects of rapid chilling of carcasses and time of deboning on weight loss and technological quality of pork semimembranosus muscle

The effect of rapid air chilling of carcasses in the first 3 h of chilling at −31 °C (then at 2–4 °C, till 24 h post-mortem) and the possibility of earlier deboning (8 h post-mortem) after rapid air chilling, compared to conventional air chilling (at 2–4 °C, till 24 h post-mortem) on weight loss and technological quality (pH value, tenderness, drip loss, cooking loss and colour - L^*a^*b^* values) of pork M. semimembranosus was investigated. Under the rapid chilling conditions, weight loss was 0.8% at 8 h post-mortem and increased to 1.4% at 24 h post-mortem when weight loss was 2.0% under conventional chilling. Carcasses that were rapid chilled had significantly lower (P < 0.001) internal temperature in the deep leg at 4 (25.7 °C), 6 (13.0 °C), 8 (6.2 °C) and 24 h (3.8 °C) post-mortem compared to conventional chill treatment (32.7, 24.2, 19.1 and 5.1 °C, respectively). Rapid chilling reduced significantly (P < 0.05) the rate of pH value decline at 8 h (6.02) post-mortem in M. semimembranosus compared to conventional chill treatment (5.88). Compared to conventional chilling, in M. semimembranosus deboned in different time post-mortem, rapid chilling had a positive significant effect on drip loss (P < 0.05, muscles deboned 8 h post-mortem), cooking loss (P < 0.001) and incidence of pale colour (L^* value). Rapid chilling i.e. rapid chilling and earlier deboning had neither positive nor negative significant effects (P > 0.05) on other investigated technological quality parameters of M. semimembranosus (tenderness, a^* value and b^* value) compared to conventional chilling.     

Development of schedule to steaming prior to drying and its effects on <Emphasis Type="Italic">Eucalyptus grandis</Emphasis> × <Emphasis Type="Italic">E. urophylla</Emphasis> wood

To investigate the influence of moisture content (MC) and steaming temperature on defects developing during steaming prior to kiln drying, mass loss, heat transfer, microstructures, extractives, and chemical transformation of Eucalyptus grandis?×?E. urophylla specimens (with moisture content of 120, 70, 60, 50, 40, 30, 20%) were observed in this study. Specimens of each experimental moisture content were steamed at 80, 100, and 120?°C for 4 h after pre-heating at atmospheric pressure, respectively. Results revealed that it was most beneficial to conduct steaming at 100?°C when the moisture content was approximately 50% after air drying when stagewise heating-up and continuous steaming schedule were adopted. Under this condition, there was a notable decrease in defects including edge bends, surface splits, and inner splits. Steaming was also a drying period characterized by various extents of mass loss. Changes in microstructures and extractive contents proved the increasing permeability of steamed wood. Deacetylation and crosslinking reactions happened in the hemicellulose of the sample materials, which contributed to the loss of hemicellulose after treatment.     

Effect of surface-active stabilizers on the surface properties of coconut milk emulsions

Previously we have demonstrated improved stability of coconut milk emulsions homogenized with various surface-active stabilizers, i.e., 1 wt% sodium caseinate, whey protein isolate (WPI), sodium dodecyl sulfate (SDS), or polyoxyethylene sorbitan monolaurate (Tween 20) [Tangsuphoom, N., & Coupland, J. N. (2008). Effect of surface-active stabilizers on the microstructure and stability of coconut milk emulsions. Food Hydrocolloids, 22(7), 1233–1242]. This study examines the changes in bulk and microstructural properties of those emulsions following thermal treatments normally used to preserve coconut milk products (i.e., −20 °C, −10 °C, 5 °C, 70 °C, 90 °C, and 120 °C). Calorimetric methods were used to determine the destabilization of emulsions and the denaturation of coconut and surface-active proteins. Homogenized coconut milk prepared without additives was destabilized by freeze–thaw, (−20 °C and −10 °C) but not by chilling (5 °C). Samples homogenized with proteins were not affected by low temperature treatments while those prepared with surfactants were stable to chilling but partially or fully coalesced following freeze–thaw. Homogenized coconut milk prepared without additives coalesced and flocculated after being heated at 90 °C or 120 °C for 1 h in due to the denaturation and subsequent aggregation of coconut proteins. Samples emulsified with caseinate were not affected by heat treatments while those prepared with WPI showed extensive coalescence and phase separation after being treated at 90 °C or 120 °C. Samples prepared with SDS were stable to heating but those prepared with Tween 20 completely destabilized by heating at 120 °C.     

Laboratory Process Development and Physicochemical Characterization of a Low Amylose and Hydrothermally Treated Ready-to-Eat Rice Product Requiring No Cooking

A low amylose and hydrothermally treated ready-to-eat rice product that requires no cooking was prepared in the laboratory. Hot soaking for 1–3 min with subsequent variable steaming at open and under pressures remarkably altered the kernel and flour properties. Increase in water absorption and lowering of cooking time with extent of steaming were prominent. Soaking of the product at 50 °C for 20 min gave texture values more similar to cooked samples. The viscosity parameters of hot soaking alone were in between those of hot soaking with open steaming and pressure steaming. Pressure steamed samples exhibited almost constantly increasing slurry viscosity throughout the heating and cooling phases of the rapid viscosity analyzer profile. Steaming variably altered the native A-type X-ray diffraction pattern. Pressure steaming of samples with 3 min hot soaking caused complete loss of the A-type conformation with feeble peaks for B- and V-type patterns. The open steamed samples showed peaks for all A-, B-, and V-type patterns. No endotherms for amylose-lipid complexes were however found in the differential scanning calorimetry of the pressure steamed samples. The raw rice flour was highly resistant to α-amylolysis. In open steamed samples, steaming severity decreased the hydrolysis rate indicating formation of enzyme-resistant fractions, while pressure steamed samples showed higher digestibility with treatment severity.     

蒸制时间对牦牛肉品质影响的模型构建与分析

以蒸制牦牛肉为研究对象,将初始条件一致的牦牛肉在相同温度(100℃)条件下分别蒸制40、60、80、100、120 min,之后对不同蒸制时间下的牛肉嫩度、保水性、p H、色泽、蛋白质含量、脂肪含量、水分含量等品质指标进行测定,同时利用主成分分析(principal component analysis,PCA)法结合感官评定构建蒸制牦牛肉的品质评价模型并结合模糊数学法对感官评分进行综合比较。结果表明:牦牛肉色泽、嫩度、保水性受蒸制时间影响变化较显著(p0.05),蒸制60 min较适于传统牦牛肉蒸制工艺,在此条件下的牛肉剪切力为5.33 kg,色彩值为12.15,WHC为91.45%,均为最佳,其蛋白质含量为37.01%,脂肪含量为3.71%,水分含量为57.80%,均较正常。运用PCA法所建模型的第一、二主成分特征根均大于1,累计贡献率达到86.469%,可以较好地反映蒸制牛肉品质指标构成的原始信息。该模型判断出不同蒸制时间的蒸制牛肉品质优劣顺序为:60 min80 min40 min100 min120 min,与模糊数学感官评分结果呈极显著正相关(p0.01),进一步证实了此模型的客观可靠性。     

Green tea extract as a natural antioxidant to extend the shelf-life of fresh-cut lettuce

Green tea extract (GT) was evaluated as a preservative treatment for fresh-cut lettuce. Different quality markers, e.g. respiration, browning, ascorbic acid and carotenoid content were evaluated. GT concentration (0.25, 0.5 and 1 g 100 mL^− 1) and temperature (20 °C and 50 °C) were tested. Optimal GT treatment (0.25 g 100 mL^− 1 at 20 °C) was compared with chlorine (120 ppm at 20 °C). High GT concentrations (0.5 g 100 mL^− 1 and 1.0 g 100 mL^− 1) maintained better prevent ascorbic acid and carotenoid loss than 0.25 g 100 mL^− 1 GT and chlorine. GT increased browning of samples, probably due to the content of polyphenols of the treatment; the use of heat-shock reduced this negative effect. GT and heat-shock combined also showed negative effects, reducing the antioxidant content (ascorbic acid and carotenoids). No significant differences were observed between chlorine and optimal GT (0.25 g 100 mL^− 1 at 20 °C) in browning appearance and sensory properties. GT better kept the antioxidant activity of the samples than chlorine.

Industrial relevance

An alternative treatment for minimally processed Iceberg lettuce is tested, based on its antioxidant capacity. Minimally processed industry is constantly looking for new treatments to avoid the use of chlorine which is a standard at the moment.     

Changes in ginsenosides and antioxidant activity of Korean ginseng (Panax ginseng C.A. Meyer) with Heating Temperature and Pressure

This study was carried out to investigate the changes of ginsenoside compositions and antioxidant activity of fresh ginseng induced by thermal processing at different temperatures (25, 100, 121, and 150°C), pressure (0.1, 10, 20, and 30 MPa), and soaking solvents (water and ethanol). The levels of ginsenosides were similar trend with the pressure of 0.1–30 MPa, while there were significantly differences in heated ginseng with heating temperature and soaking solvent. When water and ethanol was used, the ginsenoside compositions significantly changed at 100 and 121°C, respectively, and it was rapidly decreased at 150°C. After heating, the level of 3 ginsenosides (Re, Rf, and Rg1) decreased and that of 5 other ginsenosides [Rb1, Rb2, Rb3, Rc, and Rg2(S)] increased up to 121°C compare to raw ginseng. Ginsenoside F2, F4, Rg2(R), Rk3, Rh4, Rg3(S), Rg3(R), Rk1, and Rg5, which was absent in raw ginseng, was detected in heated ginseng. Especially, ginsenoside Rg3(S), Rg3(R), Rk1, and Rg5 were remarkably produced after thermal processing. After heating, the phenolic compounds (1.43–11.62 mg/g), 50% inhibition concentration (IC₅₀) value (1.48–3.11 mg/g), and ABTS radical scavenging activity (0.66–9.09 mg AA eq/g) of heated ginseng were increased.     

高效液相色谱法同时测定人参制剂中20 种人参皂苷方法的建立

为了更加有效评价人参制剂生产质量,建立了一种同时测定人参制剂中20 种人参皂苷的高效液相色谱方法。结果表明,20 种人参皂苷Rg1、Re、Rg2、Rg3、Rg5、Rf、F1、F2、Rc、Rd、Rb1、Rb2、Rb3、Rh2、compound K、20（R）-Rh1、Rk3、Rh4、原人参二醇及原人参三醇均得到良好分离,线性关系良好（R≥0.999 2）。该方法快捷简便、稳定可靠,能够精确全面检测分析人参皂苷含量,对于人参加工品及其制剂的质量控制更为全面准确可行。     

Kinetics of cowpea starch gelatinization and modeling of starch gelatinization during steaming of intact cowpea seed

Steaming of cowpea seeds prevents weevil infestation during storage. Physicochemical changes such as starch gelatinization from steaming may lead to seed resistance to weevil penetration and digestion. A kinetics of starch gelatinization was constructed and incorporated in a heat and mass transfer model to quantitatively investigate starch gelatinization in intact seeds during steaming. The outer layers of steamed seeds (0.5 mm thick) were removed by a specially designed grinding device to measure degree of starch gelatinization (DG). The predicted DG in the outermost layer of seeds was found to be in good agreement with experimental data. The average relative error for DG was 14.6%.     

Effect of thermal pre-treatment on the phenolic and protein profiles and oil oxidation dynamics of golden flaxseeds

The food industry is interested in the application of thermally pre-treated flaxseeds because the treatment improves their sensory acceptability and reduces anti-nutrient contents. However, it may influence the health benefits of flaxseed compounds. The changes in the phenolic and protein profiles, and in situ oil oxidation dynamics after steaming or roasting of flaxseeds were analysed to study this effect. The results showed that the pre-treatment of flaxseeds did not affect the content of major flaxseed phenolics. Steaming and roasting considerably changed the flaxseed protein profile. The thermally induced protein aggregation and/or cross-linking occurred. The most significant changes were found for the 13 and 53 kDa proteins. Flaxseed roasting deteriorated the oil oxidative stability significantly more than steaming. These changes may decrease the nutritional quality and shelf life of roasted or steamed flaxseeds. They should be monitored when pre-treated flaxseeds are intended to be used as a food ingredient.     

Application of Kubelka–Munk analysis to the study of translucency in fresh-cut tomato

In order to assess the development of translucency in fresh-cut tomato (Lycopersicum esculentum cv. Belissimo) during refrigerated storage, two experiments were conducted. In the first one, tomato slices obtained from fruits at breaker and at red stage were stored at 5 ± 0.5 °C and monitored at regular intervals for 9 days. In the second one, slices obtained from fruits at the light-red stage were stored at 5 ± 0.5 °C, 9 ± 0.7 °C and 13 ± 0.7 °C for 4 days. Intact (control) fruits were stored at the same conditions and sliced immediately before the evaluations. In both experiments, translucency was assessed using Kubelka–Munk analysis and through visual evaluation using a scale from 0 to 4. The translucency of cut tomato slices increased during storage in both experiments. Fruits at red stage got translucent faster than fruits at breaker stage and the intensity of translucency was also higher for more ripe fruit. The storage temperature did not influence significantly the development of translucency, indicating that the water soaking of the pericarp tissue is not a result of chilling injury. The K/S (absorption coefficient/scattering coefficient) ratio increased during storage for cut fruits and remained practically constant for intact fruits, reflecting the effects of treatment observed visually. Additional experiments indicated that the removal of the locular gel combined or not with washing and drying the slice cut surface inhibited the development of translucency.

Industrial relevance

The development of translucency is a common alteration in the appearance of fresh-cut fleshy tissue after processing, which renders the product unappealing for consumption. It is of interest for the fresh-cut industry to be able to assess the development of translucency and then evaluate the effect of different procedures in its occurrence and intensity. This paper presents the use of Kubelka–Munk analysis, a technique of widespread use in other fields like printing and painting, to assess the development of translucency in sliced tomato and to study how this process is affected by storage temperature and maturity stage of the fruit.     

Evaluation of air-dried soy protein isolate-rice noodles prepared via combined treatment with microbial transglutaminase and glucono-δ-lactone

In this study, the effects of steaming treatments during the preparation of structurally enhanced air-dried rice noodles were investigated. Soy protein isolate-rice noodles (RNS) were combined (COM) with microbial transglutaminase (MTG) and glucono-δ-lactone (GDL), and steamed for 5 (S5) or 10 (S 10) min followed by air-drying to yield air-dried RNS-COM-S5 and RNS-COM-S10, respectively. Control samples were air-dried rice flour noodles (ADRN), steamed for 5 or 10 min before air-drying (ADRN-S5 and ADRN-S10). Compared to other air-dried RNS prepared without steaming, RNS-COM-S5 and RNS-COM-S10 showed a reduction in cooking time (5.35 min) and cooking loss (7.11%) and increased cooking yield (125%), supposedly due to low gelatinisation enthalpy, while retaining textural and mechanical properties, significantly higher (P < 0.05) than the controls. The scanning electron micrographs showed that all steamed air-dried noodles also had larger hollows, which could be responsible for the improved cooking qualities. In general, the relative order of starch crystallinity resulting from steaming treatment decreased in all steamed noodles, and RNS-COM1-S10 showed the highest order. The treatment of RNS with MTG and GDL yielded air-dried noodles with a more compact structure. Steaming is necessary to improve the rehydration characteristics of the air-dried noodles without sacrificing textural and mechanical qualities.     

Effect of a 10-day ageing at 30°C on the texture of dry-cured hams processed at temperatures up to 18°C in relation to raw meat pH and salting time

The aim of this study was to investigate the effect of a 10-day ageing at 30 ± 2 °C on the texture of dry-cured hams processed at temperatures up to 18 ± 2 °C for 12 months in relation with raw ham pH and salting time. Three pH groups (semimembranosus muscle at 24 h post-mortem: Low pH < 5.7, Medium pH = 5.7  pH  5.9, and High pH > 5.9), three salting times (6 d, 10 d and 14 d) and two ageing temperatures (18 °C and 30 °C) were investigated. Physicochemical characteristics, instrumental and sensory texture and product sliceability were evaluated on biceps femoris and semimembranosus muscles. Hams with pH_SM24 < 5.7 should be avoided in order to reduce the incidence of texture problems in dry-cured ham elaboration. Texture problems are especially important in hams with a reduced salt content that are mechanically sliced (not frozen). A 10-day ageing at 30 °C could be useful for reducing the soft texture problems in dry-cured hams processed at temperatures up to 18 °C for 12 months without affecting the product flavour.