Kinetics of ultrasonic extraction of polyphenols,anthocyanins and tannins from five different New Zealand grape pomaces

Polyphenols were extracted from five kinds of New Zealand grape pomace (Sauvignon Blanc, Pinot Gris, Gerwurztraminer, Merlot and Pinot Noir) at 30, 50 and 70 °C in an ultrasonic generator. The extraction kinetics for total phenol, anthocyanin and tannin were determined. The results of dynamics study showed that the extraction of total polyphenols, anthocyanin and tannin followed first-order reaction kinetics during the extraction at 30, 50 and 70 °C. The total phenolic content, anthocyanin conten, and tannin content of water–ethanol extracts from grape pomaces were compared, and the parameters in the extraction kinetics equations were determined. The extraction results showed that the Pinot Noir pomace extract had the highest total phenolic content of 59.95 mg GAE g⁻¹ pomace and tannin content of 79.93 mg EE g⁻¹ pomace. The anthocyanin content in Merlot pomace extract was the highest, which was 4.50 CE g⁻¹ pomace. The results might be of great significance for the development of grape pomace or its polyphenol and/or anthocyanin components as an antioxidant source with natural and inexpensive benefits.     

葡萄籽超微粉添加对曲奇饼干香气的影响

将葡萄籽超微粉碎并添到曲奇饼干中,探究其对曲奇饼干香气成分及感官品质的影响。采用气相色谱-质谱联用仪分别检测了普通葡萄籽粉、葡萄籽超微粉及添加超微粉前后曲奇饼干的香气成分,并结合偏最小二乘判别分析法研究葡萄籽超微粉对曲奇饼干香气成分的影响。结果显示,超微粉碎后香气物质的种类虽未发生明显的改变,但香气成分的相对含量显著增加。葡萄籽超微粉添加比例为5%时,烘烤香比较浓郁。当添加比例达到10%时,曲奇饼干整体风味较为复杂,包括苦杏仁味、香蕉味、水果味/青草味、面包味以及坚果味。采用9点享乐法感官品评结果可以看出,葡萄籽的添加可以为饼干带来可感知的变化,添加比例为5%时,香气得分最高。葡萄籽超微粉会给曲奇饼干香气带来积极的影响,添加比例在10%以内均可被消费者接受。     

层压复合工艺优化

文章采用正交组合实验,对复合织物的剥离强度、耐静水压、透湿和透气性能进行分析。利用灰色近优综合评定,得出最优工艺。     

Optimization of sugar release from banana peel powder waste (BPPW) using box-behnken design (BBD): BPPW to biohydrogen conversion

Optimization of pre-treatment conditions has been achieved for total sugar release from banana peel powder waste (BPPW) feedstock modelled through a three-level Box-Behnken design (BBD) of the response surface methodology (RSM). A series of various runs were executed at varied acid (H₂SO₄) concentrations (0.05%–0.15% v/v), incubation periods (1 h–3 h) in water bath at 95 °C and alkali (NaOH) concentrations (0.05%–0.15% v/v) according to the Box-Behnken design (BBD). From RSM the significant values of incubation period, acid concentration and alkali concentration were obtained as 3 h, 0.095% v/v, and 0.05% v/v respectively. The maximum total sugar release was reported as 5243.62 μg/ml which was highly close to the predicted value (5010.07 μg/ml). The model P- value (0.001), R-sq (98.26%), (adj) R-sq (95.14%) and (pred) R-sq (79.56%) obtained through ANOVA justified the results. The mutual impact of alkali and incubation period had the highest effect on total sugar release from dried banana peel powder, followed by mutual impact of acid and incubation period based on ANOVA (Analysis of Variance) results.Under optimized conditions of pre-treatment six different substrate concentrations (1%, 3%, 5%, 7% and 9% w/v) of BPPW was hydrolyzed and used to obtain volumetric bio-hydrogen evolution. The highest cumulative volumetric bio hydrogen gas 43 ml H₂/30 ml media was achieved at 5% w/v of pretreated BPPW. The substrate concentration above 5% w/v resulted in lowered fermentation process owing to product and substrate inhibition.     

Influence of grape composition and winemaking on the anthocyanin composition of red wines of Tannat

The anthocyanin composition of Tannat red wines obtained with four winemaking techniques was evaluated in different years. The wines were elaborated with traditional maceration (TM), cold pre‐fermentative maceration, delayed extraction of anthocyanins and extended maceration. Two vinifications were carried out for each technique, employing 70 kg of grapes in each one. The anthocyanin composition of wines was analysed by high‐performance liquid chromatography–diode array detection. The results confirm the fundamental role of the grape composition on the anthocyanin composition of the wines. The winemaking had an important effect on the total concentration of anthocyanins and also may modify the anthocyanic profile of wines. The wines obtained with TM had higher or similar content of anthocyanins than those elaborated with the other techniques. Canonical discriminant analysis of data showed that vintage has a greater effect on anthocyanin concentration than winemaking techniques.     

Carrying and spine loading

The advantages and disadvantages of different methods of carrying objects on spine loading are still not fully understood. Previous studies have either examined the effects of carrying using physiological measures or examined isolated spine segments using biomechanical models. Additionally, most studies have been restricted to only a small number of carrying conditions. Very few studies have attempted to examine the various factors influencing spine loading together. To improve understanding of interacting factors on carrying, this study assessed the lumbar spine loads of 16 subjects as they assumed six styles of carrying at two weight levels and two activity levels (walking vs. standing). Concurrent with each trial, a subject-specific biomechanical model was used to assess spine forces over the full lumbar spine. Most carrying methods in the trials resulted in relatively low levels of spine loading. Anterior/posterior (A/P) shear loading was the only spine-loading dimension that reached biomechanically meaningful levels. Two carrying conditions, with bins carried in front of the body, significantly increased A/P shear compared with other carrying styles. This increase appeared to be due to the greater moment arms occurring in these conditions. Many of the other carrying styles produced A/P shears that were similar to those observed when carrying nothing at all. Of all the tasks, the backpack carry characteristically produced especially low spine loads. The findings of the study suggest that to achieve optimal carrying in terms of spine loading, loads should be positioned close to the body, even when carrying relatively light loads.     

The evaluation of a practical biomechanical model estimating lumbar moments in occupational activities

To estimate the mechanical load on the low back in manual materials handling, the Static Strength Prediction Model (SSPM, University of Michigan) is widely used in the occupational field. It requires (for practical reasons) only a small number of input variables (five body segment angles, standing height, total body mass, external load on the hands) on which basis the moment at the lumbo-sacral intervertebral joint (beside other parameters) is computed. The dynamic character of the activities is ignored in the calculations. To evaluate the validity of the SSPM in various situations, lumbar moments in lifting/lowering activities at different lifting techniques and speeds obtained by the SSPM, were compared with those obtained by a more comprehensive dynamic model (DM). An analysis of variance showed significant effects (p = 0.001) of the biomechanical model applied and the lifting speed used on the peak lumbar moment values. No effects of lifting technique were found. The differences in results from the SSPM and DM were dependent on the lifting speed: the SSPM peak lumbar moments were on average 9% (not significant), 21% (significant atp = 0.005) and 42% (p = 0.0001) smaller compared to the DM moments in the slow (mean velocity in a complete lifting/lowering cycle, 0.2 m s^?1), normal (0.4 m s^?1) and fast (0.8 m s^?1) speed condition respectively. The results indicate that the static/dynamic difference between the models is a major source for the different lumbar moments, while other differences between the SSPM and DM are of minor importance.