山竹壳膳食纤维结合酚提取工艺的优化及抗氧化活性分析

摘 要: 目的 对比酸法、碱法和酶法水解对山竹壳膳食纤维中的结合酚(bound polyphenols in Mangosteen peel, MDF-PP)的提取效果及抗氧化性, 在这三种提取方法得到的结合酚中选择得率最高和抗氧化性最强的方法进行工艺优化。方法 首先依次采用α-高温淀粉酶、木瓜蛋白酶和糖化酶对山竹壳进行酶解, 得到膳食纤维(mangosteen peel dietary fibre, MDF)。随后分别采用酸法水解、碱法水解和酶法对MDF-PP的提取, 并分别测定了所得MDF-PP的DPPH自由基清除率, 最后选择得率最高, 抗氧化性最强的方法进行MDF-PP提取的单因素实验及响应面优化。结果 碱法水解提取MDF-PP效果最好且抗氧化性最强。由响应面法得到最佳碱法水解提取工艺条件为氢氧化钠浓度为24 moL/L, 碱水解时间为4 h, 液固比为30:1 (mL/g)。在该条件下MDF-PP的得率为(88.44±1.10) (mg GAE/10 g DW),与预测值相接近。结论 本次实验建立的响应面模型良好, 可用于预测碱法提取山竹壳时MDF-PP的得率。MDF-PP具有较好的抗氧化性, 为MDF-PP的提取和进一步的活性研究提供了参考价值。     

Antioxidant activity and dietary fibre of Prensal Blanc white grape (Vitis vinifera) by‐products

Stem and pomace of a white grape (Vitis vinifera) variety, Prensal Blanc, were studied for the first time: general composition and dietary fibre components together with the total soluble polyphenol content and antioxidant activity. Both by‐products present high contents of total dietary fibre (TDF), 790 g kg^?1 d.m. (stem) and 716 g kg^?1 d.m. (pomace). Values of the soluble dietary fibres in relation to TDF differed: 5% (stem) and 14.4% (pomace). Similar values of Klason lignin were found: 229 g kg^?1 (stem) and 278 g kg^?1 (pomace), however, the pomace exhibited more than twice the content of the condensed tannins (168 g kg^?1) with regard to the stem (79 g kg^?1). Notable were the high resistant protein contents of both by‐products. Stem and pomace showed appreciable amounts of total soluble polyphenols (87 g kg^?1 against 35 g kg^?1 respectively). The free radical scavenging capacity of the former by‐products was determined using the 2,2‐diphenyl‐1‐picrylhydrazyl radical (DPPH) method, obtaining EC₅₀ values of 0.79 g d.m. g^?1 DPPH (stem) and 1.32 g d.m. g^?1 DPPH (pomace). These data shows that both vinification by‐products from the Prensal Blanc variety are a good source of dietary fibre and have antioxidant properties.     

Physiological Effects of Eicosapentaenoic Acid (EPA) and Docosahexaenoic Acid (DHA)—A Review

Marine lipids have long been documented to be the major source of polyunsaturated fatty acids (PUFAs), especially n-3 fatty acids such as eicosapentaenoic acid (EPA; 20:5 n-3) and docosahexaenoic acid (DHA; 22:6 n-3). Both EPA and DHA have been documented to have significant influence on biochemical and physiological changes in the body. Although these long chain PUFA exert positive influences on human nutrition and health, there are also some controversies pertaining to the functioning of these n-3 PUFAs including the extent of their requirement by the body. As marine lipids have been thoroughly reviewed often, the present review mainly focuses on works related to physiological effects of EPA and DHA.     

Effect of the addition of whole‐grain wheat flour and of extrusion process parameters on dietary fibre content,starch transformation and mechanical properties of a ready‐to‐eat breakfast cereal

This study evaluates the effect of the incorporation of whole‐grain wheat flour (WGWF) and of extrusion process parameters on the nutritional and technological quality of breakfast cereals. The corn flour‐based breakfast cereals were elaborated in a twin‐screw extruder following a rotatable central composite design with varied WGWF (0–100%), feed moisture (14–24%) and zones 3 and 4 barrel temperature (76–143 °C). Dietary fibre and resistant starch were significantly increased with WGWF addition. Total and digestible starch showed a decrease when WGWF increased. The RVA parameters were significantly affected by all the extrusion conditions and WGWF content. The cell structure of the extrudates was dependent of WGWF and moisture.     

Effect of extrusion variables on antioxidant activity,total phenolic content and dietary fibre content of gluten‐free extrudate from germinated Chenopodium (Chenopodium album) flour

A Box‐Behnken design was used to study the effects of feed moisture content (18–20%), barrel temperature (115–135 °C) and screw speed (225–275 rpm) on the responses; antioxidant activity, total phenolics, dietary fibre, colour (L‐value), hardness, expansion ratio, water absorption index and overall acceptability for development of gluten‐free extrudate based on germinated Chenopodium album flour. Second‐order polynomial fitted model showed that temperature most significantly (P ≤ 0.05) affected the antioxidant activity (AoxA), total phenolics (TPC), expansion ratio, hardness and overall acceptability (OA). Antioxidant activity, total phenolic content and dietary fibre of extrudate varied from 11.56 to 15.93%, 56.77 to 81.28 mg/100 g and 18.65 to 22.06 g/100 g, whereas the lightness and hardness of extrudates ranged from 64.02 to 68.35 and 12.26 to 19.49 N, respectively. The results of this study validate the production of functional and acceptable snack product made from C.  album flour by extrusion cooking.     

Metabolic stress disinfection and disinfestation (MSDD): a new,non‐thermal,residue‐free process for fresh agricultural products

Physical manipulations generating cycles of expansion and compression forces were combined with low vapor concentrations of natural disinfecting chemicals to disinfect and disinfest simultaneously and rapidly fresh agricultural products. Lethality in various fungi, plant and human pathogens and in all biological stages of selected arthropods was demonstrated with fresh fruits and vegetables. The combined process modifies the respiratory metabolism, affects biological structures, causes displacement of the O₂/CO₂ gaseous equilibrium and induces chemical toxicity at the cellular level. In aerobic microbes, oxygen metabolism is rapidly disrupted, causing biocidal effects. In larval, pupal and adult insect stages, irreversible structural damage of the tracheal system prevents the formation and causes the elimination of air reserves. In arthropod eggs, damage in essential structural features and dehydration of the chorion affect their ability to diffuse and use oxygen. The MSDD process is rapid (<4 h), effective (100% insect controls, >5 log₁₀ microbial reduction), reproducible, practical, economically competitive and applicable to large volumes of commodities. It causes minimal or no sensory/functional effects in host commodities. If developed commercially, it can be a single alternative to a broad spectrum of post‐harvest pesticides for disinfection and a likely alternative to methyl bromide fumigation or to irradiation for the post‐harvest control of arthropods. Copyright © 2006 Society of Chemical Industry     

Marine omega‐3 (n‐3) phospholipids: A comprehensive review of their properties,sources, bioavailability,and relation to brain health

For several decades, there has been considerable interest in marine‐derived long chain n‐3 fatty acids (n‐3 LCPUFAs) due to their outstanding health benefits. n‐3 LCPUFAs can be found in nature either in triglycerides (TAGs) or in phospholipid (PL) form. From brain health point of view, PL n‐3 is more bioavailable and potent compared to n‐3 in TAG form, as only PL n‐3 is able to cross the blood–brain barrier and can be involved in brain biochemical reactions. However, PL n‐3 has been ignored in the fish oil industry and frequently removed as an impurity during degumming processes. As a result, PL products derived from marine sources are very limited compared to TAG products. Commercially, PLs are being used in pharmaceutical industries as drug carriers, in food manufacturing as emulsifiers and in cosmetic industries as skin care agents, but most of the PLs used in these applications are produced from vegetable sources that contain less (without EPA, DPA, and DHA) or sometimes no n‐3 LCPUFAs. This review provides a comprehensive account of the properties, structures, and major sources of marine PLs, and provides focussed discussion of their relationship to brain health. Epidemiological, laboratory, and clinical studies on n‐3 LCPUFAs enriched PLs using different model systems in relation to brain and mental health that have been published over the past few years are discussed in detail.     

Detection of clenbuterol in beef meat,liver and kidney by mid‐infrared spectroscopy (FT‐Mid IR) and multivariate analysis

Mid‐infrared spectroscopy (FT‐Mid IR) coupled with multivariate analysis was used to predict clenbuterol in beef meat, liver and kidney. A SIMCA model was also developed to discriminate between pure (beef meat, liver and kidney) and spiked with clenbuterol samples (beef meat‐clenbuterol, liver‐clenbuterol and kidney‐clenbuterol). The best models to predict clenbuterol concentrations were obtained using the partial least squares algorithm (PLS) with a R² > 0.9 and SEC and standard error of prediction <0.296 and 0.324, respectively. The SIMCA model used to discriminate pure and spiked with clenbuterol samples showed 100% correct classification rate. Methods detection limit was 2 μg kg^?1. FT‐Mid IR coupled with chemometrics could be a simple and rapid screening tool for monitoring clenbuterol in beef meat, liver and kidney implicated in food poisoning. This method could be use for screening purposes.     

Rheology and bread‐making performance of gluten‐free formulations affected by different levels of sugar beet fibre,hydroxypropylmethylcellulose and water

This study investigated the application of hydroxypropylmethylcellulose (HPMC) (2%, 3%, 4%), sugar beet fibre (SBF) (3%, 5%, 7%) and water (210%, 220%, 230%) into maize‐based gluten‐free (GF) formulations and their effects on the GF batter rheology and bread quality. HPMC incorporation in higher amounts reduced the compliance values of GF batter samples and increased the values of dynamic moduli indicating an improvement in the GF batter elastic characteristic. The same course of action with a less pronounced influence on mentioned rheological parameters had SBF addition. GF bread quality evaluation in terms of specific loaf volume and crumb texture (hardness, cohesiveness and springiness) reveals that HPMC and SBF incorporation at higher levels enhanced these quality parameters. The inclusion of HPMC and SBF coupled with adequate water content can improve the nutritional value of GF bread without negative influence on bread quality.     

Selection of dietary fibres for sucrose replacement in functional Chhana‐murki (Indian Cottage cheese‐based dessert) and their effect on sensory,physical and instrumental texture parameters

With a wide range of beneficial effects on human health, various dietary fibres such as microcrystalline cellulose (MCC), inulin, oat fibre and wheat fibre were screened based on their bulking ability in the functional Chhana‐murki (FCM) with respect to sensory and physical properties. Sensory scores were maximum for MCC at 7.5% having optimum moisture content and water activity and minimum hardness, whereas oat and wheat fibres increased the hardness of the product while decreasing the moisture content and water activity thus lowering the sensory scores. Further, replacement of MCC with inulin in 1:1 ratio improved the product characteristics.     

Physicochemical properties and bioactive function of Japanese grape (Hovenia dulcis) pomace insoluble dietary fibre modified by ball milling and complex enzyme treatment

The study investigated the effects of ball milling and enzymolysis on the structural characteristics, physicochemical properties and bioactive function of Hovenia dulcis pomace insoluble dietary fibre (HIDF). Ball milling and enzymolysis effectively decreased the particle size and zeta potential of HIDF. The swelling power (SP), water solubility index (WSI) and apparent viscosity of HIDF were effectively enhanced (P < 0.05) after ball milling and enzymolysis. Scanning electron microscopy detection showed that the surface and internal structures of HIDF were destructed by the modified treatment. Ball milling and enzymolysis treatment disrupted the intermolecular hydrogen bonds and crystalline structure of HIDF per Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD) analysis. Furthermore, the inhibition rate of HIDF on α-glucosidase and α-amylase was significantly increased by modification. All HIDF significantly improved the lipid metabolism of hyperlipidemic mice, with the modified IDF providing a stronger effect.     

Effect of pre‐treatment and smoking process (cold and hot) on chemical,microbiological and sensory quality of mackerel (Scomber scombrus)

The sensory, hygienic, toxicological and nutritional profiles of hot‐ and cold‐smoked mackerel samples were studied with various pre‐treatments. The panellists assessed all smoked samples as barely to quite acceptable products whilst the product immersed in 120 g kg^?1 sodium chloride and 60 g kg^?1 fructose prior to smoking was assessed as very acceptable regarding its sensory characteristics. The available lysine in all hot smoked samples was reduced to the same extent (32%) whilst a very good correlation (r = 0.912) was observed between loss of available lysine and colour formation of the cold‐smoked products, indicating the high contribution of lysine in the interactions with carbonyls. Histamine was found in highly unacceptable levels even in the unprocessed samples (600 mg kg^?1) and strongly increased (2220 and 2250 mg kg^?1) in the cold‐ and hot‐smoked samples, respectively, due to all treatments. These are levels which would be expected to cause symptoms of scombrotoxin poisoning. Benzo(a)pyrene, fluoranthene and perylene were at high levels both in cold‐ (2.1, 4.3 ± 0.04 and 7.2 ± 0.05 µg kg^?1) and hot‐smoked samples (9.2, 7.8 ± 0.03 and 9.4 ± 0.14 µg kg^?1, respectively) and were, as expected, influenced by the temperature. The aerobic bacteria remained at acceptable levels, since salt and high temperature prevent bacterial growth. Copyright © 2004 Society of Chemical Industry     

Comparison of simultaneous distillation extraction (SDE) and solid‐phase microextraction (SPME) for the analysis of volatile compounds in dry‐cured ham

Simultaneous distillation extraction (SDE) and solid‐phase microextraction (SPME) using a carboxen/polydimethylsiloxane fibre were compared for their effectiveness in the extraction of volatile compounds from dry‐cured ham samples. A higher number of compounds was detected using SPME owing to the use of a solvent delay time in the GC‐MS analysis of SDE extracts. SPME was more efficient in extracting low molecular weight and high volatility compounds, while SDE was able to extract compounds with low volatilities that were not extracted using SPME. Both techniques satisfactorily extracted most volatiles previously highlighted as odour‐active compounds in dry‐cured ham. However, the ratio between some compounds from lipid oxidation and those from degradation of amino acids was much lower in SDE extracts than with SPME, which could be a consequence of the development of Strecker degradation of amino acids during distillation in SDE owing to the high temperatures used. Similarly, diunsaturated aldehydes detected in SDE extracts were absent using SPME, probably owing to oxidation of polyunsaturated fatty acids in SDE as a consequence of the temperature during extraction. Copyright © 2004 Society of Chemical Industry