Colour and label evaluation of commercial pasteurised red juices and related drinks

Despite growing demand by consumers for healthy beverages, artificial colours are still widely used. Levels of anthocyanins and artificial colours were determined by HPLC with UV-Vis detection in red orange juices and other red beverages (nectar, juice-based, health, carbonated and sports drinks). The contribution of pigments to the visible colour of the beverage was calculated. Red orange juice samples contained about 34?mg?l^?1 of anthocyanins, which were responsible for about 92% of the visible colour. Red juice-based drinks, containing from 0% to 30% of red orange, berry, grape or pomegranate juices, had low levels of anthocyanins (about 7?mg?l^?1) and high levels of E129 (about 32?mg?l^?1), which were responsible for about 90.7% of the colour of these beverages. Red health drinks, enriched with vitamins and polyphenols, contained from 3% to 50% of red fruit juices. Also in this case the E129 levels were higher (about 22?mg?l^?1) than anthocyanins (about 9?mg?l^?1), and were responsible for the colour of the beverages (76.1%). High levels of artificial colours were found in red orange carbonated drinks, but in comparable amounts with those found in the other beverage samples, while anthocyanins were only present in trace amounts. Although all of the beverages claimed to contain red fruits on the labels, no correlation was found between the level of anthocyanins and the declared percentage of red fruits. These labels generally conformed with the requirements of the law, but food product labels can often be misleading to consumers about the real characteristics of the product.     

Contamination by moulds of grape berries in Slovakia

This paper describes the first map, albeit partial, of toxigenic fungi re-isolated from grape berries collected in three out of the six most important Slovakia winemaking areas in two different periods of the harvest year 2008. Low temperatures and high relative humidity during July 2008 favoured the development of grape fungal diseases that cause rots such as Plasmopara, Uncinula, Botrytis, Metasphaeria, Elsinoë, and Saccharomycetes. In the analysed samples, the following genera of toxigenic fungi were identified in the range of 1–4%: Aspergillus, Alternaria, Cladosporium, Epicoccum, Fusarium, Penicillium, Rhizopus, Ulocladium, and Trichoderma Trichothecium, while the genera Aspergillus, Alternaria, Fusarium, and Penicillium were in the range 11–29%. A. niger, A. carbonarius, some strains of A. carbonarius–with ‘crystals’ and strains of A. uvarum–uniseriate were identified; these species are considered ochratoxigenic (able to produce variable amounts of toxins). In addition, a non-ochratoxigenic strain of A. ibericus and a Fusarium strain able to biosynthesize small amount of fumonisins, beauvericin, and enniatins were identified. P. expansum, able to produce citrinin, represents 29.7%, of the Penicillium genus together with P. verrucosum, P. glabrum, P. citrinum, and P. crustosum. An analysis for the identification and quantification of the main toxins: ochratoxin A, fumonisins, beauvericin, enniatins, and fusaproliferin was performed on grape samples; it was consistent with the results of the mycological analysis. Toxigenic fungi should be checked throughout the years and their occurrence compared with all environmental factors to avoid health risks.     

果汁非酶褐变的机制及控制措施

本文阐述了果汁非酶褐变的机制：焦糖化反应、美拉德反应、抗坏血酸氧化分解和多元酚氧化缩合,并对目前常用的抑制果汁非酶褐变的方法进行了综述.     

芦荟、梨、黄瓜复合果蔬汁的加工工艺

以芦荟、梨和黄瓜为主要原料，研究了营养保健型复合果蔬汁的制作工艺。采用对比、正交实验设计，确定了最佳工艺参数，该产品具有较高的营养价值。     

爬山虎果实色素的提取及其性质的初步研究

对爬山虎(ParthenocissustricuspidatePlanch)果实天然红色素的提取方法及理化性质进行了初步研究,结果表明:爬山虎果实色素的最大吸收峰为528nm,表现出花青素的基本特征;以甲酸为溶剂时提取效果最好;随着pH值的变化,色素表现出多种变构体;Fe3 、Fe2 等金属离子及氧化剂H2O2对其稳定性有较大影响;该色素在较高的温度、较强的酸性及自然光照条件下都较为稳定。     

长白山区刺五加果糕的配方及工艺研究

以刺五加浆果为原料,通过正交实验探讨糖酸比、胶凝剂、温度等因素对产品品质的影响。结果表明产品的最佳配方为白砂糖37.9%,柠檬酸2.95%,复合胶中黄原胶2.1%、海藻酸钠2.1%、琼脂1.58%,产品具有独特组织状态、色泽和口感。污染刺五加果糕的主要微生物是交链孢菌和黄曲霉菌。微波灭菌为优选灭菌方法。     

Fast headspace-enantioselective GC-mass spectrometric-multivariate statistical method for routine authentication of flavoured fruit foods

This study describes a rapid total analysis system (TAS) to detect the authenticity of fruit-flavoured foods and beverages by on-line combining headspace solid phase microextraction (HS-SPME) with enantioselective GC-MS (Es-GC-MS) and statistical multivariate methods (PCA, HCA). Peach, coconut, apricot, raspberry, as fruits mainly characterised by γ- and δ-lactones as chiral markers, strawberry (α-ionone, linalool, nerolidol, ethyl 2-methylbutyrate, 2-methylbutyric acid and γ-lactones) and melon (ethyl 2-methylbutyrate and 2-methylbutanol) were investigated. The system was developed by (a) optimising non-equilibrium HS-SPME sample preparation, (b) speeding-up ES-GC using cyclodextrin derivatives as chiral selectors with conventional and narrow-bore columns and (c) elaborating data by multivariate methods. The resulting TAS affords a reduction of the time needed for the whole analytical process from about 150 min to 20-50 min (67-87% of the current routine method) depending on matrix, sampling and analysis conditions and Es-GC columns.     

Nondestructive measurement of soluble solid content of navel orange fruit by visible-NIR spectrometric technique with PLSR and PCA-BPNN

A relationship was established between the soluble solid content (SSC) of navel orange fruit determined by destructive measurement and visible-near infrared diffuse reflectance spectra in the wavelength range of 350-1800 nm. Multiplicative scatter correction (MSC) and standard normal variate correction (SNV) were applied to the spectra, partial least squares regression (PLSR) and back propagation neural network (BPNN) based on principal component analysis (PCA) were used to develop the models for predicting the SSC of intact navel orange fruit. Thirty-eight unknown samples were used to evaluate the performance of these models. The principal component analysis-back propagation (PCA-BPNN) method with MSC spectral pretreatment obtain the best predictive results, resulting in correlation coefficient, root mean square error of prediction (RMSEP), average difference between predicted and measured values (Bias) of 0.90, 0.68 °Brix and 0.16 °Brix, respectively. Experimental results indicate that PCA-BPNN is a suitable tool to model the non-linear complex system, with additional advantages over PLSR, and the vis/NIR spectrometric technique can be used for measuring the SSC of intact navel orange fruit, nondestructively.     

黑加仑、蓝莓复合果醋饮料的研发

本试验采用二次发酵法,通过对黑加仑、蓝莓复合果醋的酒精发酵及醋酸发酵的优化,最终确定黑加仑、蓝莓复合果醋的酒精发酵最佳工艺为:黑加仑果汁与蓝莓果汁3:2复合,在初始糖度8°BX、初始pH3.8、28℃发酵6d、。醋酸发酵最佳条件为:发酵温度35℃,通风量为l:0.10～0.15(V/V/min),酒精含量6.0%,接种量8.0%,初始pH5.5。黑加仑、蓝莓复合果醋饮料配方:12%复合果醋、5.5%白砂糖、2%蜂蜜、0.1%食盐、0.06%复合香料,评分为92分。工艺调整后的放大生产产品质量仍稳定、达标。产品具有食醋清香和黑加仑、蓝莓果香,酸味柔和,风味独特。     

黑莓果醋生产的优化工艺研究

研究黑莓果醋的酿造工艺条件,利用响应面法得到最佳醋酸发酵工艺条件.结果表明,黑莓果醋的醋酸发酵的最适宜工艺条件为:醋酸菌的接种量11.5％,酒精浓度7.7％,醋酸菌的适宜生长温度为30℃,果醋酸度达到4.5％.