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关键词： Feta cheese   Physicochemical parameters   Volatiles   Fatty acids   Geographical differentiation   Chemometrics  

摘要： The present study aimed to differentiate feta cheese samples produced in northern Greece according to geographical origin. In 2006 the EU, through Council Regulation (EC) 510/2006 succeeded in giving a competitive advantage to the quality and diversity of the Union's agricultural production by adopting PDO (Protected Designation of Origin) and PGI (Protected Geographical Indication) regulations among EU members. Feta cheese has been approved as a Greek PDO product in 2008. Feta cheese samples from the regions of Ioannina, Arta, Thessaloniki, Larissa and Evros, were subjected to physicochemical, fatty acid and volatile compounds analyses. Using multivariate statistical analysis (MANOVA/LDA) and the cross-validation method, cheese samples achieved a correct classification rate of 61.8%, 65.8% and 88.2% based on physicochemical parameters, volatile profile and fatty acid composition, respectively. Fatty acids were the most efficient parameters for the differentiation of cheese samples. When all three above parameters were combined the correct classification rate of cheese samples increased to 89.5%.

关键词： Palm empty fruit bunches   Pyrolysis   Experimental design   Antioxidant properties  

摘要： Residues of the palm oil agro-industry (palm empty fruit bunches - EFB) were pyrolysed to produce biofuels. Effects of several parameters on the slow pyrolysis process were evaluated using the central compound rotational design (DCCR) for modelling and optimization the process conditions aiming the maximum yield of bio-oil. After pyrolisis and using various approaches the products were characterized with emphasis on bio-oil. The response surface methodology and desirability function indicate that the temperature was the most influential parameter in regard to the liquid yield, in which the optimum pyrolysis conditions were: temperature of 628.2 degrees C and N-2 flow rate of 0.259 L/min. The empirical relationships for the bio-gas, bio-oil, and bio-char were carried out from a second-order polynomial equation adequately describing the nonlinear behaviour of the experimental data with a precision of approximately 85%. Gas chromatography-mass spectrometry (GC-MS) and Fourier Transformer infrared (FTIR) analysis shows that bio-oil has a high content of oxygenated compounds with four main components: hexadecanoic acid methyl ester (25.57 area%), nonane (12.51 area%), n-hexadecanoic acid (10.66 area%) and phenol (10.13 area%). Moreover, high-performance thin-layer chromatography (HPTLC) analysis showed the bio-oil is very promising for biodiesel-based automotive additives preventing oxidation of the bisallylic methylene groups and the consequent generation of free radicals. Biochar showed low yield (27.52%) but good energy capacity, with a calorific value of 19.27 MJ/kg. Regarding to gases production, CO2 and CH4 are the main compounds observed in optimized conditions suggestion its use like raw material in the energy production.

关键词： Ultrasound-assisted immersion freezing   Chicken breast   Quality   Physicochemical properties  

摘要： This paper evaluated the impact of air freezing (AF), immersion freezing (IF) and ultrasound-assisted immersion freezing (UF) at different power levels (125, 165, 205 and 245 W) on the muscle quality and physicochemical properties of chicken breast. As the ultrasonic power increased, the total freezing time of the UF samples first decreased and then increased. UF at 165 W (UF-165) remarkably shortened the freezing time of the samples. Microstructure analysis showed that UF-165 samples had the smaller and more uniform ice crystals. In addition, UF-165 effectively reduced the thawing and cooking losses (P<0.05) compared to those of the AF and IF samples. Low field nuclear magnetic resonance analysis proved that the T-21 and T-22 of the UF-165 samples were shorter than those of the AF and IF samples (P<0.05), which meant that UF-165 reduced the mobility and loss of immobilized water. Overall, the appropriate ultrasonic power had a positive effect on maintaining the quality of frozen chicken breast. (C) 2020 Elsevier Ltd and IIR. All rights reserved.

关键词： 物理化学   高等职业教育   教材  

ISBN: (纸本)9787564377038

摘要： 本书是高等职业教育“物理化学”课程教材，内容包括：气体、热力学第一定律、热力学第二定律、相平衡、电化学、化学动力学、表面现象、胶体与大分子溶液等。本书针对高职高专学生的实际情况，力求深入浅出，精简了公式的推导过程，着重强调公式的使用条件和应用范围。为了便于教学，本书在例题和习题的选编上也力求典型并注重启发性，在强调物理化学理论基础的同时，突出专业特点，注重物理化学原理在化工、医药方面的应用，书中例题多结合化工、医药知识，适合高职院校化工与制药等相关专业使用。

关键词： honey   electronic nose   electronic tongue   sensory analysis   adulteration  

摘要： Honey is produced by honeybees and is used as a food and medical product. Adulteration of honey has been a problem for several years now because of the relatively high price of honey on the market according to its valuable composition. The aim of our study is to determine the physicochemical properties of authentic Hungarian linden and acacia honeys (pure samples or manipulated ones blended with sugar syrup) as well as commercially available blends of European Union (EU) non-European Union (non-EU) honeys. Authentic linden and acacia were blended with sugar syrup at 10%, 20% and 50% concentration levels, and physicochemical properties were determined according to the methods of the International Honey Commission. Our objectives also included testing of the performance of electronic sensory techniques (electronic tongue (ET) and electronic nose (EN)) in the detection of adulteration, and the results are compared to the sensory profile analysis. The results provide good average recognition and prediction abilities for the classification of adulterated and authentic honeys (>90% for ET and higher than >80 for EN). Misclassifications were found only in the case of honey with 10% added sugar syrup. The methods were also able to reveal adulteration of independently predicted samples.

关键词： Calcium  

摘要： Finger millet being underutilized but highly nutritious millet was explored for nutritional characteristics. Twelve cultivars of finger millet were found to be a potential source of proteins (7.19%-12.56%), crude fibers (3.17%-5.83%), crude fat (1.07%-1.87%), and ash or mineral content (2.81%-3.61%) as well as a rich source of minerals such as Cu (0.61-1.62 mg/100 g), Mn (4.01-7.44 mg/100 g), Fe (3.97-8.04 mg/100 g), Zn (2.08-4.50 mg/100 g), and Ca (318-659 mg/100 g). Cultivars were screened out for the highest content of calcium and the cultivar GPHCPB-149 richest in calcium (659 mg/100 g) was utilized for supplementation in biscuits at different proportions, that is, 0, 25, 50, and 75%. A significant (p <= .05) increase in the calcium and crude fiber contents was reported with increased incorporation of finger millet in biscuits. Sensory evaluation studies concluded that finger millet flour was successfully incorporated up to 50% in wheat flour for the preparation of biscuits. Practical applications The study showed that finger millet is a rich source of nutrients and has great potential to be utilized for the development of functional bakery products. It can be successfully incorporated up to 50% with wheat flour for the preparation of functional bakery products. Finger millet incorporated biscuits were found to contain higher levels of crude fiber, calcium, iron, and zinc contents than control biscuits and may offer the inherent health benefits of finger millet to the consumers by alleviating the deficiency of calcium and prevention of other lifestyle diseases.

关键词： Malted sorghum   Starch   Malting   Rheology   Amylose   Reducing sugars  

摘要： The objective of this study was to evaluate the physicochemical changes that occur in sorghum starch during malting to determine its potential in the beer industry. The results showed that the physicochemical properties of amorphous amylose and amylopectin of starch over time are modified during the germination while its crystalline structure is not affected. During the different stages of malting the SEM images showed the progress of the enzymatic attack in the starch granule. Germination and the increase in reducing sugars supported amorphous starch degradation. The X-ray diffraction pattern confirmed that during malting, the crystalline structure in starch remained without changes. The pasting profile showed high values for peak and final viscosity, once the sorghum was soaked and decreasing over the malting process. These changes are associated with starch degradation and amylopectin debranching, increasing the reducing sugars.

关键词： frozen storage   mozzarella cheese   proteolysis   oxidation  

摘要： High-moisture mozzarella is one of the most-exported Italian cheeses worldwide, but its quality is affected by storage. Freezing is regarded as a solution to decrease product waste, extend market reach, and increase con-venience, but its effect on quality has to be estimated. In this study, the details related to proteolysis, physico-chemical properties, and sensory quality parameters of high-moisture mozzarella as a function of frozen storage (1, 3, and 4 mo) and subsequent refrigerated storage after thawing (1, 3, and 8 d) were evaluated. Frozen cheeses stored at -18 degrees C showed a higher extent of pro-teolysis, as well as different colorimetric and sensory properties, compared with the fresh, nonfrozen control. Sensory evaluation showed the emergence of oxidized and bitter taste after 1 mo of frozen storage, which supports the proteolysis data. The extent of proteolysis of frozen-stored cheese after thawing was greater than that measured in fresh cheese during refrigerated stor-age. These results help better understand the changes occurring during frozen storage of high-moisture moz-zarella cheese and evaluate possible means to decrease the effect of freezing on the cheese matrix.

关键词： TP microcapsules   LZM   PVA coating   Sustained-release   Antibacterial mechanism  

摘要： Tea polyphenol (TP) has excellent preservation effect on the aquatic product, however, its long-term antibacterial and preservation property is poor due to its volatilization. Therefore, a novel sustained -release formulation of TP should be developed for improving the applicability. In this study, the TP microcapsules/LZM-PVA composite coatings with gradual slow release properties were prepared by tape-casting method. Its micro-morphology was characterized and its physicochemical properties were determined. Meanwhile, the antibacterial properties and mechanism of the composite coatings were studied with Pseudomonas fluorescens and Shewanella putrefaciens, the dominant spoilage bacteria in aquatic products, as the objects. The results show that the addition of TP and other substances affects the structure of PVA coatings, and changes the intermolecular force of PVA, the coatings is wrinkled and denser, which effectively improve the mechanical properties of the PVA coatings, and finally lead to the decrease of air permeability. Among them, the TP microcapsules/LZM-PVA composite coating has the best mechanical properties, the least amount of CO2 and water vapor penetration. The results of antibacterial experiments show that the PVA coating without preservatives has no antibacterial property. Compared with the bacterial cells treated by the corresponding composite coatings without LZM, the integrity of the cell membrane is poor and the permeability is higher after treated by the composite coating with LZM, which is due to the synergistic antibacterial effect of TP and LZM. More importantly, when TP is replaced by TP microcapsules, the antibacterial ability of the composite coatings is poor at the initial stage. However, TP is embedded in the space network structure formed by CS-sodium tripolyphosphate. TP in the coatings can be released slowly from microcapsules to coatings, and then from coatings to the culture medium, which prolong the antibacterial effect time and c

关键词： Suspensions (fluids)  

摘要： Tropical fruits have organoleptic and nutritional characteristics that are desired by consumers. The cape gooseberry (CG), strawberry (S), and blackberry concentrate (BC) contain a large number of bioactive compounds. The aim of this research was to determine the influence that a composition of a suspension based on CG, S, and gum arabic (GA) had the stability of a colloidal system. The emulsion was homogenized. A central composite experimental design was used and the independent variables were: % of cape gooseberry solids (STC) (50%-62%), strawberry solids (STS) (18%-24%), and gum arabic solids (STGA) (0.4%-0.6%). The dependent variables were viscosity (mu), zeta potential (zeta), particle size (D-10, D-50, D-90), total solids (STCS), spectral stability index (R), and antioxidant activity (ABTS and DPPH). The suspension was experimentally optimized with the following results: STC:50%, STS:18.9%, STGA:0.6%, mu:485.27 +/- 8.46, |zeta|:20.03 +/- 1.04, D-10:14.41 +/- 1.61, D-50:165.20 +/- 3.36, D-90:428.52 +/- 17.53, STCS:11.20 +/- 0.18, R:0.22 +/- 0.03, ABTS:1,307.41 +/- 18.71, and DPPH:1632.56 +/- 73.19. Experimental validation of the optimal suspension formulation conditions showed good results, which meant that a stable suspension was obtained with high antioxidant activity. Practical applications The following research establishes the optimal formulation of a suspension based on strawberry, blackberry, and cape gooseberry. This was carried out in order to guarantee a quality feed (high in antioxidants and physicochemical stable) for the spray-drying process. It is well-known that obtaining a good product in a powder form depends largely on the good quality of the feed suspension. The cape gooseberry, strawberry, and blackberry are fruits with a great variety of bioactive compounds, although they have a short shelf life when they are in a fresh stage. Thus, it is considered important to develop products that largely preserve the nutritional properties of these frui