Inhibitory effects of litchi (Litchi chinensis Sonn.) flower-water extracts on lipase activity and diet-induced obesity

Litchi flower–water extract (LFWE) contains plenty of phenolic acids, flavonoids, condensed tannins, anthocyanins, and proanthocyanidins. In this study, we used eight male rats per group that were assigned randomly to one of the following dietary group: (1) normal-caloric diet and distilled water; (2) hypercaloric diet (HCD) and distilled water; (3) HCD and 2.5% LFWE; (4) HCD and 5% LFWE for 10 weeks. As results, LFWEs demonstrated a suppressive (p < 0.05) effect on in vitro lipase activities; meanwhile, larger sizes of livers, perirenal and epididymal adipose tissues, and cell sizes of epididymal adipose tissues in hypercaloric-diet-fed group were decreased (p < 0.05) by drinking LFWEs, especially in 5% LFWE-treated groups. Increased (p < 0.05) serum cholesterol and liver lipid levels were measured in hypercaloric-diet-fed rats. However, drinking LFWEs also decreased (p < 0.05) those levels to that similar to the NCD group, whereas drinking LFWEs resulted in higher (p < 0.05) faecal lipid concentrations. It also corresponded to the liver TNF-α and IL-1β values which were ameliorated (p < 0.05) in hypercaloric-diet-fed rats with LFWEs. Therefore, the result of this investigation match the anticipation, which LFWE indeed possesses a potential nutraceuticals for anti-obesity effects.     

Vital Characteristics of Litchi (Litchi chinensis Sonn.) Pericarp that Define Postharvest Concepts for Thai Cultivars

To assess the fruit-specific determinants of pericarp browning, litchi pericarp was characterized in terms of appearance, the polyphenol pattern as specified by HPLC-DAD-MS ⁿ without and after thiolysis, and the activities of polyphenol oxidase (PPO) and peroxidase (POD) by exploring “Kwang Jao,” “O-Hia,” “Kim Cheng,” and “Chacapat” fruit on the respective harvest day, “Hong Huey” fruit also throughout 52 days of cold storage (5 °C, 95% relative humidity). At harvest, PPO activity was maximum for “Kim Cheng” pericarp (126 μkat/hg), whereas POD activity was striking for that of “O-Hia” (512 μkat/hg, including membrane-bound isoforms). Flavan-3-ol and proanthocyanidin patterns were consistent for all cultivars. However, cultivars with sharp-pointed and round–obtuse protuberances differed in pericarp anthocyanin and flavonol glycosylation patterns. The molar ratio of cyanidin 3-O-rutinoside to its glucoside was ≤6:1 for “Hong Huey” and “Kwang Jao,” but ≥43:1 for “Kim Cheng” and “Chacapat” pericarp. Long-term storage gave evidence of two key processes involved in pericarp browning: (1) PPO-mediated oxidation of abundant (?)-epicatechin (1.4–2.0 g/hg), resulting in dark brown pigments, and (2) microcrack-induced formation of light brown surface scurf, supposably with involvement of POD. Accordingly, an improved scheme for litchi pericarp browning was proposed. As regards recommendable postharvest concepts for each cultivar, “Chacapat” suited most for long-distance transports due to its overall low susceptibility to pericarp browning. Properties of “O-Hia” litchi, being prone to surface scurf formation, suggested preferred distribution via domestic markets. High contents of flavonols (e.g., quercetin glycosides, 166 mg/hg) and A-type-linked procyanidins (e.g., procyanidin A2, 1,092 mg/hg) qualified pericarp of “Hong Huey” litchi as raw material for polyphenol extracts exerting antioxidant properties.     

Anti-Inflammatory Effects of Lychee (Litchi chinensis Sonn.) Seed Peptide Hydrolysate on RAW 264.7 Macrophage Cells

Lychee (Litchi chinensis) seeds, a by-product from the canned lychee processing, were hydrolyzed using various concentrations of proteases (Alcalase, Flavourzyme, and Neutrase). The protein hydrolysate produced with Neutrase at a concentration of 50 mg/mL exhibited the highest free radical scavenging activity. After ultrafiltration, the fraction containing peptides of less than 650 Da was purified by using gel filtration chromatography into G1–G3. The G1 fraction exhibited the highest activity and was further purified by reversed phase high performance liquid chromatography (RP-HPLC). Four fractions (H1–H4) were isolated and exhibited efficient nitric oxide (NO) scavenging activity. The G1 fraction inhibited NO production in lipopolysaccharide (LPS) stimulated RAW 264.7 cells with down-regulation of inducible nitric oxide synthase (iNOS) and interleukin-6 (IL-6). The results showed that lychee seed peptide hydrolysates exhibited potent anti-inflammatory activities, suggesting the peptides may be useful as additives to health products such as functional foods and/or pharmaceuticals.     

Effects of high-pressure treatment on the extraction yield, phenolic content and antioxidant activity of litchi (Litchi chinensis Sonn.) fruit pericarp

As a promising technique, high-pressure extraction (HPE) method was used to extract bioactive compounds from litchi fruit pricarp. The study involved in different experimental factors such as solvent, ethanol concentration (35-95, v/v), material to solvent ratio (1:25-1:100, w/v), acidic medium, extraction pressure (200-500 MPa), time (2.5-30 min) and temperature (30-90 °C). The extraction yield, total phenolic contents, 1,1-diphenyl-2-picrylhydrazyl radical scavenging activity and superoxide anion scavenging capability of the HPE sample were examined and then compared with those of ultrasonic extraction and conventional extraction samples. The application of HPE obtained higher extraction yield compared to other extraction methods. However, there were no significant differences ( P  >   0.05) in the total phenolic content and the antioxidant activities among these various extractions. Compared with some conventional extraction method, the HPE exhibited higher extraction efficiency in terms of higher extraction yield and extraction time.     

Antioxidative and anti-inflammatory effects of polyphenol-rich litchi (Litchi chinensis Sonn.)-flower-water-extract on livers of high-fat-diet fed hamsters

Gentisic acid and epicatechin are two major compounds in phenolic acids and flavonoids of litchi-flower-water extracts (LFWEs), respectively. Increased (p < 0.05) serum lipids and liver size/lipid, damage/inflammatory indices, TBARS value, CRP level, MMP-9 activity, and decreased (p < 0.05) liver GSH and TEAC levels, and SOD, CAT and GSH-Px activities were observed in high-fat-diet fed hamsters compared to normal-fat-dietary hamsters. Those biochemical values of high-fat-diet fed hamsters were significant improved (p < 0.05) by drinking LFWEs. In addition, these improvements on liver damage induced by a high-fat diet were also evidenced in the histopathological examination of livers where less microvesicular steatosis and no necrotic/inflammatory cells were observed in high-fat-diet fed hamster drinking LFWEs. Therefore, protective effects of LFWEs on liver damage of high-fat-diet fed hamsters can be accounted for antioxidative properties and anti-inflammatory effects of LFWEs.     

Effect of Calcium Lactate, 4-Hexyl Resorcinol and Vacuum Packing on Physico-chemical, Sensory and Microbiological Qualities of Minimally Processed Litchi (Litchi chinensis Sonn.)

Litchi (Litchi chinensis Sonn.) fruits are very susceptible to pericarp browning which adversely affects consumer acceptability even though the aril portion remains in excellent condition. Litchi arils (litchis) were treated with a solution containing 0–2% (w/v) calcium lactate (CL), 0–0.02% (w/v) 4‐hexyl resorcinol (4‐HR) and 1% potassium sorbate. The pH of solution was adjusted to 4.0 with citric acid. Treated litchis were packed in polystyrene trays, over‐wrapped with polypropylene film, vacuum‐packed (0, 47409.3, 94831.9 Pa) and stored at 4 ± 2 °C. Drip losses, pH, total soluble solids (TSS), sensory attributes and microbiological quality of stored samples were estimated. A four‐factor, three‐level experimental design (D₆ Hokes design) with 19 experiments was chosen. Mathematical models were developed to analyse and predict the effect of CL, 4‐HR, in‐package vacuum and storage time on the responses. TSS, pH and sensory scores decreased significantly (P 0.01), whereas drip losses and microbial count increased significantly (P 0.01) with time. Drip loss was significantly (P 0.1) reduced by addition of CL. 4‐HR prevented browning and changes in colour score during storage were significantly less. Vacuum in packages exerted significant (P 0.01) effect over pH, TSS, sensory and microbiological qualities of minimally processed litchis.     

Effects of three drying methods on polyphenol composition and antioxidant activities of Litchi chinensis Sonn.

Food Science and Biotechnology - The aim of this study was to investigate the effects of three different drying methods, freeze drying (FD), vacuum drying (VD) and oven drying (OD) on phenolic...     

Preparation,characterisation and antioxidant activities of litchi (Litchi chinensis Sonn.) polysaccharides extracted by ultra‐high pressure

Litchi (Litchi chinensis Sonn.) is a fruit containing many nutrients. Based on a three level, three‐variable Box‐Behnken design, response surface methodology, was used to optimise the process of ultra‐high pressure (UHP) assisted extraction of litchi polysaccharides (LCP). The optimal extraction conditions were as follows: pressure 460 MPa, treatment time 17 min and liquid–solid ratio 15. The experimental yield for extracting LCP was 12.01% under the optimal conditions. The LCP had a high polysaccharide and low protein content. GC results showed that LCP was composed of rhamnose, fucose, mannose and galactose with the corresponding molar percentages of 7.89, 46.45, 9.71 and 19.63. Infrared analysis showed that LCP had a typical spectrum of an α‐configuration pyranose ring. Antioxidant activity analysis revealed that LCP possessed a strong reducing power and 2,2‐diphenyl‐1‐picrylhydrazyl (DPPH) scavenging activity and could protect against the damage of hydroxyl radicals. The investigations demonstrated that UHP could be a valuable way to separate polysaccharides from litchi pulp, and LCP may be potentially developed to an antioxidant for food industries.     

Effects of spontaneous and inoculated fermentation on the volatile profile of lychee (Litchi chinensis Sonn) fermented beverages

The aim of this study was to evaluate the contribution of yeast to the volatile profile of beverages obtained by the fermentation of lychee must through inoculated (Saccharomyces cerevisiae strains UFLA CA116 , UFLA CA1183 and UFLA CA1174 ) and spontaneous fermentation. Higher alcohols and esters were the primary volatiles detected by SPME/GC–MS. A Principal Component Analysis indicated similarities between UFLA CA116 and UFLA CA1183 and between UFLA CA1174 and spontaneous fermentation. Changing the yeast strain used in the fermentation process has the potential to modulate the volatile profile of fermented beverages. The beverage produced by the inoculation of yeast CA1183 showed the most complex aroma profile compared to the other beverages.     

Effect of some thermal and chemical pretreatments on smoked Oyster mushroom quality

The effect of different thermal and chemical pretreatments on quality and enzyme activities of smoked mushroom was investigated. Mushrooms were blanched (water and steam) and dipped in different concentrations of sulphites (SO₂), hydrogen peroxide (H₂O₂), ethylene‐di‐amine tetra‐acetic acid (EDTA) and citric acid for 10 min before smoking. Enzyme activities, colour characteristics, microbiological and sensory examinations were carried out every 2 weeks up to 8 weeks of storage in refrigerator at 4 °C. Results could be concluded that smoked mushroom pretreated with SO₂, H₂O₂ and steam blanching had the best colour values, the better score for all sensory characteristics and lower non‐enzymatic browning compared with other pretreatments. The most effective pretreatment against total aerobic bacteria and yeast & moulds were citric acid, EDTA and steam, and then smoking of mushroom can be attributed to the reduction of microbial counts. The most effective pretreatments on quality and safety of smoked mushrooms were H₂O₂ and steam. It can be concluded that thermal and chemical treatments, rather than smoking of mushroom, reduce enzyme activities and are suitable to preserve mushrooms.     

避雨栽培条件下红宝石无核葡萄光合特性初探

以欧亚种葡萄红宝石无核为试材,使用LI-6400光合作用测定系统,对其在避雨栽培条件下果实膨大期的光合特性进行了研究.结果表明:葡萄叶片的净光合速率(Pn)日变化呈双峰曲线,具有明显的光合午休现象.光饱和点(LSP)为1500цmol/(m2·s),光补偿点(LCP)为55.48 u mol(m2·s); C02饱和点(CSP)为1200 u mol/mol,CO2补偿点(CCP)为45.04 u mol/mol;表观量子效率(AQY)为0.0436,羧化效率(CE)为0.0461.     

不同预处理对马铃薯片浸渍速率及感官品质的影响

采用理化测定和感官评定相结合的方法考察了烫漂、冷冻、微波干燥、烫漂+冷冻四种预处理方式对马铃薯片在麦芽糊精溶液中的浸渍速率及感官品质的影响。结果表明,以45%的糊精溶液为浸渍液,在45℃下进行浸渍,烫漂+冷冻的预处理方式浸渍速率最大,在30min时即已达最大浸渍量的80%,基本满足工艺要求;经此处理浸渍后的薯片外形平整饱满,色泽浅黄半透明,质感厚实。烫漂+冷冻的预处理方式可作为马铃薯脆片加工中浸渍工序的最佳预处理措施。     

Effect of processing on the texture and structure of raspberry (cv. Heritage) and blackberry (cv. Thornfree)

This paper reports separate studies of the effect of pre-treatments (CaCl₂, low methoxyl pectin (LMP), and combined solutions) and the effect of freezing method (at four different rates) and thawing mode (at two different rates) on objective parameters, structure and sensory characteristics of fresh raspberries and blackberries. After that, the effect of a complete freezing process combining the best pre-treatments with the best freezing/thawing conditions found for each fruit was investigated. Kramer Shear Cell (KSC), back extrusion, compression and multiple penetration tests were used to measure fruit texture objectively. For calcium and LMP pre-treatments, which were applied separately, texture parameters were significantly higher in samples treated at the highest concentrations (100 mM of CaCl₂ for both fruits and 0.3 and 3% of LMP for raspberry and blackberry, respectively) compared to fresh controls. Blackberry structure was more susceptible than raspberry structure to the effect of pre-treatments. For the combined pre-treatments, the highest texture parameters were found in the samples treated with CaCl₂ (100 mM) and LMP (0.1%) in the case of raspberries and CaCl₂ (100 mM) and LMP (3%) in the case of blackberries. Combined pre-treatment did not increase firmness with respect to that of samples treated only with calcium, which indicates that CaCl₂ preserved the raspberry structure more efficiently during processing. Fruits frozen by forced convection with liquid nitrogen vapour at –40 °C were significantly firmer. Raspberries should be thawed at 5 °C, whereas blackberries may be thawed at room temperature. Sensory analysis showed that the blackberry structure was more resistant to freezing. In both fruits, over the complete process parameter values were again highest in the samples treated with 100 mM CaCl₂, applied either separately or in combination with LMP. In raspberry, panellists detected no significant differences between sensory texture parameters of the different samples, and in blackberry, panellists found no significant differences between any of the sensory characteristics. Multiple penetration maximum force (F _MP) was the parameter that best expressed product firmness for both fresh and frozen raspberries, whereas compression slope (S _C) best reflected changes in blackberries. SEM mainly corroborated results from objective texture parameters.     

Effect of temperature fluctuations during frozen storage on the quality of potato tissue (cv. Monalisa)

 Results are presented on the effect of different ranges of temperature fluctuation (–24 to –18°C, –18 to –12°C, –12 to –6°C, –24 to –12°C and –18 to –6°C) on the compression, shear and tension parameters of packed and unpacked frozen potato tissue. The initial temperature, duration and number (2, 4, 8, 16, 24 and 32) of fluctuations were varied. The highest parameter values occurred in samples subjected to fluctuations between –24°C and –18°C, and the lowest values in the range –18 to –6°C. The mechanical strength of the frozen tissue decreased with an increase in the number of fluctuations and in most cases was lower in the packed samples. Moisture loss was greatest in the –18 to –6°C range for pre-packed samples. Changes in the maximum compression force, as a measure mechanical damage, showed the greatest level of significance. Received: 17 June 1997     

Effect of temperature fluctuations during frozen storage on the quality of potato tissue (cv. Monalisa)

 Results are presented on the effect of different ranges of temperature fluctuation (–24 to –18°C, –18 to –12°C, –12 to –6°C, –24 to –12°C and –18 to –6°C) on the compression, shear and tension parameters of packed and unpacked frozen potato tissue. The initial temperature, duration and number (2, 4, 8, 16, 24 and 32) of fluctuations were varied. The highest parameter values occurred in samples subjected to fluctuations between –24°C and –18°C, and the lowest values in the range –18 to –6°C. The mechanical strength of the frozen tissue decreased with an increase in the number of fluctuations and in most cases was lower in the packed samples. Moisture loss was greatest in the –18 to –6°C range for pre-packed samples. Changes in the maximum compression force, as a measure mechanical damage, showed the greatest level of significance. Received: 17 June 1997     

不同架式与负载量对红地球葡萄果实品质的影响

以3年生红地球葡萄为试材,研究了不同架式及负载量对果实品质的影响.结果表明,立体棚架栽培的果实单粒重、可溶性固形物含量、固酸此等品质指标均高于平棚架和篱架,总酸含量低于二者;立体棚架新梢保留8～10个/m2较适宜;立体棚架叶片净光合速率(Pn)极显著高于棚架和篱架(P<0.01),并且叶片Pn6果实单粒重、总糖含量呈显著正相关.     

Effect of water activity and temperature on the color change of red pepper (Capsicum annuum L.) powder

Isotherm characteristics of red pepper powder and the effect of temperature and water activity (Aw) on its color change were investigated. Monolayer moisture contents of red pepper powder decreased from 0.1218 to 0.0912 g water/g solid with increasing temperature from 25 to 50°C. The color change of red pepper powder was greatly dependent on temperature and Aw. As temperature and Aw increased, red color of pepper powder increasingly faded out to become brown and tarnish black, which is mainly attributed to the degradation of carotenoid pigments and development of browning compounds. Color parameters such as Hunter-L, a, b values and other color functions as well as browning index and ASTA color values represent color changes of red pepper powder as influenced by temperature and Aw.     

不同灌溉量对设施红地球葡萄生理特性及品质的影响

为实行节水灌溉和提高红地球葡萄的质量和产量,在高寒干旱地区设施栽培条件下各生长期设置了不同灌溉量试验.结果表明,与传统漫灌方式(对照)相比,果实成熟时各处理中的叶片生理指标和果实品质表现不同,其中处理4的叶绿素含量、单粒重、穗重和可溶性固形物含量相对最高,与对照相比分别增长了20.63%、16.61%、16.62%～,48.92%;脯氨酸、丙二醛含量、SOD、POD、CAT活性相对最低,与对照相比降低了42.11%、36.09%、21.11%、49.76%和39.44%.