Chemical Composition and Effect of Processing and Flour Particle Size on Physicochemical and Organoleptic Properties of Cocoyam (Colocasia esculenta var. esculenta) Flour

This work investigated the chemical composition of cocoyam corms and cormels and the effect of processing and particle size on the physicochemical and organoleptic properties of the flours for use as soup thickener. Fresh cocoyam corms and cormels were peeled, sliced, washed, divided into four parts that were variously blanched, sulphited and sulphited/blanched. The control was not treated. The slices were sun dried (32 ± 2°C, 3 days), milled and classified with standard sieves into particle sizes of 0.1, 0.2, 0.4, 0.6 mm. The flour samples and fresh corms and cormels were analyzed for the proximate composition, ascorbic acid, anthocyanin and oxalic acid contents. The flours were also analyzed for the pH, bulk density, water and oil absorption capacities and the sensory properties of colour and texture. On dry weight basis, the protein, fat, crude fibre, ash and carbohydrate contents of the corms, cormels and flours were the same (p > 0.05). Ascorbic acid, anthocyanin and oxalic acid contents were respectively reduced from averages of 30.35, 31.58 and 173.88 mg/ 100 g (dry weight) in the corm/cormel to ranges of 8.95 — 16.28, 9.58 — 15.90 and 141.69 — 160.68 mg/ 100 g in the flours. Bulk density was increased (p < 0.05) by blanching and particle size. The water and oil absorption capacities were increased (p < 0.05) by blanching. Colour preference was improved by sulphiting, blanching and decreasing particle size. Texture preference was only affected by particle size. Acceptablility of soups from flours were not affected by treatments and particle sizes.     

Effects of Gamma Irradiation on the Chemical Composition and Antioxidant Activity of Lactarius deliciosus L. Wild Edible Mushroom

The short shelf-life of mushrooms is an obstacle to the distribution and marketing of the fresh product. There has been extensive research on finding the most appropriate technology for mushrooms preservation and a particular interest arises for wild species. Treatment by irradiation emerges as a possible conservation technique that has been tested successfully in several food products. Herein, the effects of gamma irradiation on Lactarius deliciosus (L. ex Fr.) S. F. Gray chemical composition and antioxidant activity were evaluated in samples submitted to different storage periods (0, 4 and 8 days) at 4 °C. The irradiation treatments were performed in a Co-60 experimental equipment. Nutritional value was accessed by macronutrients analysis and determination of energetic value; fatty acid, sugar and tocopherol profiles were determined by gas chromatography–flame ionization detector, high-performance liquid chromatography (HPLC) refractive index and HPLC fluorescence, respectively. The antioxidant activity was evaluated through radical scavenging activity, reducing power, lipid peroxidation inhibition and phenolics content. The obtained data show that, until 1 kGy, gamma irradiation might provide a useful alternative to ensure the quality and extend the life of mushrooms, since its effects on macronutrients, energetic value, tocopherols and antioxidant activity EC₅₀ values were less significant than the changes caused by storage time. Moreover, the chemical and nutritional composition was similar in irradiated and non-irradiated L. deliciosus samples.     

Processing Effects on Chemical,Functional and Pasting Properties of Cowpea Flour from Different Varieties

Cowpea varieties (IT88D-867-11, IT89KD-288 and MALA) were boiled, roasted, dehulled and later milled into powder. The proximate composition, functional and pasting properties as well as anti-nutritional contents (Tannin) of the product was subsequently determined. The result of the study revealed significant increase (P < 0.05) in the crude protein, crude ash, swelling power and water absorption capacity. Conversely, significant decrease (P < 0.05) was observed in crude fat, starch content, moisture content, solubility and peak viscosity. Boiled samples have significantly higher (P < 0.05) crude protein, swelling power, water absorption capacity, with concomitantly lower solubility and tannin content. Crude ash, moisture, solubility and tannin content of dehulled samples decreased significantly with an increase in protein, swelling power and water absorption capacity. However, IT89KD-288 has the highest protein content irrespective of the processing used. But raw IT89KD-288 showed highest percentage of swelling power, solubility, water absorption capacity and Tannin content. The result revealed that both boiling and dehulling will greatly reduce tannin content of cowpea.     

不同化学处理对碳纤维分散及成纸性能的影响

通过联合Zeta电位、吸光度和数码图像分析,考察了碱性预处理和不同试剂表面处理对碳纤维分散性的影响,并以碳纤维配加纸浆制取纸样,检测纸张的物理强度和体积电阻率。实验结果表明:碱性预处理可改善碳纤维分散性,吐温-80和CPAM试剂都可显著提高碳纤维分散性及成纸抗张指数和电导率,但作用机理截然不同。吐温-80通过降低固液表面张力,提高水对纤维的润湿能力,改善碳纤维分散性;CPAM则是通过形成三维空间大网络絮体,阻止碳纤维的运动聚集,来改善其在纸浆中的分散。     

Processing and storage effects on the oxidative stability of hemp (Cannabis sativa L.) oil‐in‐water emulsions

Hempseed oil was used to form oil‐in‐water emulsions, and the effect of heating, storage and light on the oxidative stability of the dispersed phase was investigated. Lipid oxidation rate increased following thermal processing and light exposure, whereas oxidation markers remained relatively unaffected during emulsions storage at 4 °C for 10 days. Induction times of the emulsions were reduced up to 26% and the concentration of thiobarbituric acid reactive substances increased up to 4.5‐fold, depending on the processing conditions. Selected berries as potential sources of natural antioxidants were screened for polyphenol and anthocyanin content in order to investigate their ability to retard lipid oxidation in comparison with a commercially available synthetic counterpart. Raspberry powder extract significantly improved the oxidative stability of hemp‐based emulsion compared with the control and was even more effective compared to a synthetic antioxidant when samples were subjected to heat treatment.     

Processing of pigmented‐flesh potatoes (Solanum tuberosum L.) on the retention of bioactive compounds

Retention of bioactive compounds in white‐ (WFP), yellow‐ (YFP), red‐ (RFP) and purple (PFP)‐fleshed potatoes after drum‐drying (DD) and Refractance Window? drying (RW) was compared with freeze‐drying (FD). Processing, generally, did not influence total phenolics. Total carotenoid was high in YFP, but decreased with DD. Both DD and RW decreased lutein concentration in YFP. The RFP and PFP had the highest total anthocyanin, and their concentrations were decreased by DD. RW decreased total anthocyanin in PFP only. Total antioxidant activity in WFP was higher with DD but lower with RW. In contrast, DD and RW drying had no significant effect on total antioxidants in YFP, RFP and PFP. Therefore, drying generally decreased antioxidants, with FD and RW retaining the highest concentration of bioactive compounds.     

Effect of drying methods on the physical properties and microstructures of mango (Philippine ‘Carabao’ var.) powder

Mango powders were obtained at water content below 0.05 kg water/kg dry solids using Refractance Window® (RW) drying, freeze drying (FD), drum drying (DD), and spray drying (SD). The spray-dried powder was produced with the aid of maltodextrin (DE = 10). The chosen drying methods provided wide variations in residence time, from seconds (in SD) to over 30 h (in FD), and in product temperatures, from 20 °C (in FD) to 105 °C (in DD). The colors of RW-dried mango powder and reconstituted mango puree were comparable to the freeze-dried products, but were significantly different from drum-dried (darker), and spray-dried (lighter) counterparts. The bulk densities of drum and RW-dried mango powders were higher than freeze-dried and spray-dried powders. There were no significant differences (P ? 0.05) between RW and freeze-dried powders in terms of solubility and hygroscopicity. The glass transition temperature of RW-, freeze-, drum- and spray-dried mango powders were not significantly different (P ? 0.05). The dried powders exhibited amorphous structures as evidenced by the X-ray diffractograms. The microstructure of RW-dried mango powder was smooth and flaky with uniform thickness. Particles of freeze-dried mango powder were more porous compared to the other three products. Drum-dried material exhibited irregular morphology with sharp edges, while spray-dried mango powder had a spherical shape. The study concludes that RW drying can produce mango powder with quality comparable to that obtained via freeze drying, and better than the drum and spray-dried mango powders.     

Effects of Minimal Processing Technologies on Jackfruit (<Emphasis Type="Italic">Artocarpus heterophyllus</Emphasis> Lam.) Quality Parameters

Jackfruit (Artocarpus heterophyllus Lam.) is a tropical fruit with high nutritional value and reported health benefits, but its commercialization is hindered by its mass (>?10 kg) and difficulty to peel. Jackfruit bulbs (JFBs) are often sold fresh, washed only with water and packaged in polypropylene containers, which minimizes their shelf life and makes it necessary to consume them shortly after purchase. Minimally processed products (MPPs) are ready-to-eat fresh-cut products, and the technologies used to produce them to allow better utilizing fruits, extending their shelf life and freshness as much as possible. This review describes reported advantages and limitations that minimal processing methods exert on JFBs. These methods include low temperatures, anti-browning agents, anti-respiratory substances, texturizing agents, controlled atmospheres, edible coatings, osmotic agents, preservatives, and UV treatments among others. Their effects on physiological and physicochemical parameters, as well as effects on shelf life and sensory attributes are also discussed. Evidence shows that minimal processing techniques are a viable option that can be used on JFBs, which preserve quality and sensory attributes by reducing metabolic reactions like respiration rate (RR) and ethylene production. Shelf life can be extended up to 50 days without changes in sensory attributes, and higher retention of bioactive compounds in comparison with untreated JFBs, but results vary with each specific treatment. Minimal processing technologies are a rapid, efficient, and reliable alternative that retain quality and extend the shelf life of fresh JFBs. With further improvements in preservation and standardization, the commercialization of jackfruit could be brought to bear.     

Chemical and antioxidative assessment of dietary turnip (Brassica rapa var. rapa L.)

The phenolic compounds and organic acids of turnip (Brassica rapa var. rapa L.) edible parts (leaves and stems, flower buds and roots) were determined by HPLC–DAD and HPLC–UV, respectively. The results revealed a profile composed of 14 phenolics (3-p-coumaroylquinic, caffeic, ferulic and sinapic acids, kaempferol 3-O-sophoroside-7-O-glucoside, kaempferol 3-O-sophoroside-7-O-sophoroside, kaempferol 3-O-(feruloyl/caffeoyl)-sophoroside-7-O-glucoside, kaempferol 3,7-O-diglucoside, isorhamnetin 3,7-O-diglucoside, kaempferol 3-O-sophoroside, 1,2-disinapoylgentiobiose, 1,2′-disinapoyl-2-feruloylgentiobiose, kaempferol 3-O-glucoside and isorhamnetin 3-O-glucoside) and six organic acids (aconitic, citric, ketoglutaric, malic, shikimic and fumaric acids). The quantification of the identified compounds showed kaempferol 3-O-sophoroside-7-O-glucoside, kaempferol 3-O-(feruloyl/caffeoyl)-sophoroside-7-O-glucoside, isorhamnetin 3,7-O-diglucoside and isorhamnetin 3-O-glucoside as the main phenolics, and malic acid as the organic acid present in highest amounts. A screening of the antioxidative potential was also performed by means of the DPPH radical scavenging assay. Turnip flower buds exhibited the strongest antioxidant capacity.