Effect of processing method on vitamin profile,antioxidant properties and total phenolic content of coconut (Cocos nucifera L.) sugar syrup

Coconut (Cocos nucifera L.) sugar is a more nutritious alternative sugar source as compared to sugar palm (Borassus flabellifer) and sugarcane (Saccharum officinarum L.). This work was aimed to investigate the browning index (BI), vitamin profile and antioxidant properties of coconut sap sugar syrups, which were produced by different processing methods: rotary evaporation (RE), microwave evaporation (ME) and open-heat evaporation (OHE). The results obtained showed that coconut sugar syrup produced by RE-60 contained high antioxidant activities [DPPH (36.71%) and ABTS (34.84%), TPC (299.87 mg per 100 g sample) and FRAP (3.74 mm )]. These values were slightly lower than those of ME and OHE. Coconut sugar syrup (RE-60) also contained higher amounts of vitamin C (1587.27 mg L⁻¹), vitamin B1 (97.44 mg L⁻¹) and vitamin B3 (19.84 mg L⁻¹) compared with those of ME and OHE coconut sugar syrups. RE-60 was the best method to produce coconut sugar syrup in a shorter time with lower browning index and higher vitamin contents.     

Production of high purity fructose from barley syrups using semi-continuous chromatography

A semi-continuous counter current chromatographic refiner, developed in this department, was used to produce high fructose syrup from an industrial barley syrup containing 42% fructose, 52% glucose and 6% maltose and oligosaccharides. The chromatographic refiner consisted of twelve 5.4 cm i.d. columns, each packed to a height of 65.5 cm with KORELA VO7C calcium charged resin, with a particle size range 150–300 μm. At a throughput of 32.1 kg sugar solids/m³ resin/h, the fructose rich product obtained was 95% pure and had a concentration of 11.3% w/v, while the glucose rich product contained only 4.5% fructose and had a concentration of 22.56% w/v.     

Clarification of date juice

Summary This study was initiated to utilize a variety of low quality dates (Qish‐Habash) so that high quality syrup could be produced by modifying the clarification process of the date juice. Five different clarification treatments were used: (1) filtration, (2) hot liming and filtration, (3) cold liming and filtration, (4) powder‐activated carbon and filtration, and (5) granular‐activated carbon and filtration. The sugar content, total soluble solids, total ash, pH, colour and purity were analysed to determine the clarification effects. The clarified juices produced by these treatments were evaporated under constant conditions to produce date syrup. Filtration, and activated carbon and filtration were the most successful treatments for the clarification of the date juice. Filtration gave the highest improvement in syrup purity (97.7%), due to the reduction of total ash by 19.5% and colour by 44.6%. Activated carbon removed the juice colour to give the lowest amount (60% in powder form and 57% in granular form), as well as reducing total ash, which led to an improved syrup purity, 92.2% in powder form and 91.4% in granular form. Liming clarification had undesirable effects, by increasing the total ash (15% in hot and 17% in cold lime), and increasing the colouring matter produced by decomposition.     

Intrinsic kinetic constants of an immobilised glucose-isomerase

The isomerization of glucose into fructose using a commercial immobilised glucose-isomerase has been studied and an initial transitory state of the enzyme, probably due to an establishment of stationary concentration profiles, was observed. Operational conditions to minimise the effects of external and internal mass transfer were determined using immobilised enzyme particles with diameters less than 0.064 mm. Thermal enzyme deactivation of the enzyme was insignificant if it was pre-treated with cobalt. The intrinsic kinetic constants of the reversible reaction Michaelis—Menten equation were calculated, in operational conditions free of mass transfer effects.     

膏浆灌浆结合高压旋喷工法在华安水电站扩建工程进水口围堰防渗中的应用

福建华安水电站扩建工程进水口围堰修建在水库中,正常水深9.0～10.0m。水电站工程始建于20世纪70年代,经过多年淤积,堰址处覆盖层深厚,透水性强。围堰基础防渗采用膏浆可控性灌浆进行处理,经检查,防渗性能满足设计要求,说明采用膏浆可控性灌浆的各种参数合理,膏浆灌浆对于处理该类地层具有优越性。     

国内外菠萝农药残留限量标准对比分析

农药最大残留限量标准是评价农产品质量安全水平的重要指标,也是国际贸易壁垒重要的技术参数,为提高农产品质量安全水平,保障人民身体健康、贸易顺畅、产业发展,许多国家、组织和地区均规定了食品中的最大农药残留限量标准。本文以菠萝为对象,梳理了我国菠萝农药登记情况,查阅整理中国大陆、中国香港、中国澳门和欧盟、美国、日本、澳大利亚、食品法典委员会等国家(地区)和组织的菠萝农药残留限量标准制定情况,并分析内在差异,总结我国菠萝残留限量标准存在的问题,并在我国菠萝用农药登记、标准制修订、风险交流方面提出了建议和措施,以期为完善我国菠萝质量安全标准体系提供参考。     

导流筒在粉浆罐中的应用

说明了以玉米为原料、干法粉碎工艺的酒精生产中,导流筒在拌料过程中的作用及在生产中的应用。     

菠萝皮厌氧发酵产沼气的研究

介绍了以菠萝皮为原料,在25℃恒温条件下,采用批量发酵工艺,进行发酵产沼气实验,实验结果表明,菠萝皮可以作为沼气发酵原料,未加碱时产沼气潜力为574.81 mL/gTS,604.30mL/gVS,甲烷含量51.34%;而加碱时产沼气潜力为568.66 mL/gTS,597.84 mL/gVS,甲烷含量52.96%。     

Identification of pyrazine derivatives in a typical maple syrup using headspace solid-phase microextraction with gas chromatography–mass spectrometry

Headspace solid-phase microextraction combined with gas chromatography–mass spectrometry was applied to identify pyrazines in a typical maple syrup characterised by plant ligneous or sawdust flavour. Carboxen/polydimethylsiloxane (85 μm) fibre and Supelcowax 10 column were selected instead of Carbowax/divinylbenzene (65 μm) fibre and VF-5ms column, respectively, because of their high capacity to extract and separate pyrazines. A total of 27 pyrazines were identified. To our knowledge, about half of these compounds had not previously been detected in maple syrup and 15 pyrazines were flavour components.     

Process development of a chocolate-flavoured peanut–soy beverage

A new beverage product was developed utilising two protein‐rich oilseed sources, namely peanut and soy. Medium‐roasted peanut flour and chocolate flavour were incorporated to offer pleasant flavour profile. The peanut–soy combination would also improve essential amino acid profile, especially that of lysine, compared with an all‐peanut product. A pilot‐plant scale beverage‐processing protocol involved filtration, homogenisation and pasteurisation as the major operating steps. Beverage formulation employed a three‐component constrained mixture design. The low‐ and high‐bound constraints were determined for peanut (30.6–58.7%), soy (28.3–43.5%) and chocolate syrup (13.0–25.9%) based on lysine content, viscosity and visual stability index values of 51‐mg g^?1 protein, 36.9 mPa s and 1.00, respectively. The beverage formulation and processing protocol thus developed were the basis for further study on consumer acceptability of the new chocolate‐flavoured peanut–soy beverage.