Comparison of FTIR, FT-Raman, and NIR Spectroscopy in a Maple Syrup Adulteration Study

ABSTRACT: Maple syrup is prone to adulteration with cheaper sugars, such as corn syrup, due to its simplicity in chemical composition. The adulterated samples were characterized by Fourier Transform infrared (FTIR) spectroscopy in the region of 400 to 4000 cm_-1. Other techniques used for detection and in characterization of samples were the near infrared (NIR; 600 to 1700nm) and Fourier Transform-Raman (FT-Raman; 400 to 4000cm_-1) spectroscopy. Quantifying and classifying adulterants using chemometrics shows that all spectroscopic methods adopted were efficient, but FTIR and FT-Raman were superior to NIR in quantitative characterization of adulterants in maple syrup.     

Methods of Antibiotic Applications as Related to Microbial Quality of Lamb by PCA and Bioluminescence

The effects of different methods of application of chlortetracycline and oxytetracycline on microbial properties of lamb meat were studied. A significant antibacterial effect of antibiotic was found on total mesophilic bacteria count. The mesophilic bacteria level was determined by two methods: the conventional method using Plate Count Agar and bioluminescence. Correlation curves of the CFU and RLU values proved two methods were highly related. Thus for the microbiology quality of meat hygiene the bioluminescence method may be used as a fast and alternative method to PCA. Note that bioluminescence requires a higher degree of skill and attention.     

CTAB提取ATP的生物荧光法快速检测细菌总数准确性研究

为降低ATP生物荧光法检测费用,本研究采用十六烷基三甲基溴化铵(CTAB)为细菌细胞ATP的提取剂,β-环糊精为中和剂,优化不同食品体系中细菌ATP的提取方法,同时检验CTAB提取ATP的生物荧光法快速检测细菌总数的准确性。结果表明:大肠杆菌、金黄色葡萄球菌、乳酸菌和枯草芽孢杆菌细胞采用CTAB提取出的细菌ATP的发光强度与细菌总数的线性相关性良好,相关系数均在0.92以上。对代表性的果汁、面、肉和奶制品经CTAB处理提取出细菌ATP后,对于细菌总数在103~107 CFU/mL的产品,根据ATP的荧光强度,能准确的判断出细菌总数,且生物荧光法与平板计数法两者检测结果的相关系数达到0.9895。但在原料肉的测定时,提取出的ATP的荧光强度与其细菌总数之间的相关性较差,为提高检测准确性,需要预先采用相关去除体细胞ATP干扰的配套试剂进行处理。     

微生物ATP提取方法及其在微波灭菌效果快速评价中的应用研究

本文对ATP发光技术中微生物ATP提取方法进行了优化研究,通过对不同提取剂提取效率的比较,发现苯扎溴铵提取效果好,并且无需稀释,能真实体现微生物细胞内的ATP水平。通过对苯扎溴铵提取时间和提取浓度的优化,结果显示采用体积分数为0.05%苯扎溴铵溶液与菌液混合3~4 min,即可将细胞内的ATP最大限度地释放出来。将该提取方法与ATP生物发光反应体系偶联,实现了对微波灭菌效果的快速评价,在短时间内即可得到可靠结果。试验比较了不同微波功率和微波时间的灭菌效果,实验结果表明,大肠杆菌ATCC25922在用2450 MHz 650w微波照射60 s时可被完全杀灭,而金黄色葡萄球菌ATCC25923则需70 s才能被杀灭。当用2450 MHz微波同样处理60 s时,650 w即可杀灭大肠杆菌ATCC25922,而金黄色葡萄球菌ATCC25923则需700 w才可被完全杀灭。     

The Microbial and Sensory Quality of Mackerel Hot Smoked in Mild Conditions

The quality indices of Atlantic mackerel, hot smoked at core temperature not exceeding 60°C, containing 14-27 g salt and 580-670 g water per kg meat, was determined just after smoking and during storage. The aerobic plate count after smoking, chilling and packing in cardboard boxes was 0-12 cfu/25 cm²of the skin of the smoked fish and 10-240 cfu/g of flesh. It was 1.9 log cycle lower than that in the frozen raw material. At 2°C, the bacterial count on the fish surface and in the meat remained unchanged for at least 3 wk. At 8°C after 14 d, the cfu in the meat of smoked fish ranged from 1.8×10²to 1.6×10⁷/g. The total count on the skin and just under the skin did not increase up to 21 d at 2 and 8°C. There was no statistically significant difference between the mean values of all evaluated sensory attributes of the smoked fish stored up to 2 wk at 2 and 8°C. These results regard products from a smoking plant of very high hygienic standard, fulfilling all EC requirements, with quality assurance system based on HACCP.     

Prediction of Microbial and Sensory Quality of Cold Smoked Atlantic Salmon (Salmo salar) by Electronic Nose

ABSTRACT: Quality changes of cold smoked salmon from 4 different smokehouses in Europe were monitored by a prototype gas-sensor array system, the FishNose. Samples were stored in different packaging (vacuum and Modified Atmosphere Packaging [MAP]) for up to 4 wk under controlled storage conditions at 5 °C and 10 °C. Quality criteria based on sensory attributes (sweet/sour, off, and rancid odor), and total viable counts and lactic acid bacteria counts were established and used for classification of samples based on the responses of the FishNose. The responses of the gas-sensors correlated well with sensory analysis of spoilage odor and microbial counts suggesting that they can detect volatile microbially produced compounds causing spoilage odors in cold-smoked salmon during storage. The system is therefore ideal for fast quality control related to freshness evaluation of smoked salmon products. Partial least squares (PLS) regression models based on samples from single producer showed better performance than a global model based on products from different producers to classify samples of different quality.     

Volume and Sensory Properties of Yellow Cakes as Affected by High Fructose Corn Syrup and Corn Oil

The effects of high fructose corn syrup (HFCS) and corn oil (CO) on volume and deformation and effects of mono- and diglyceride (MDG) and sucrose ester (SE) emulsifiers on volume and sensory properties of yellow cakes were studied. 50% HFCS gave the greatest volume; 100% HFCS decreased volume; CO increased volume. Deformation was greatest in 50% HFCS cakes with 50% or 100% CO. Simultaneous optimization of volume and deformation was predicted at 35% HFCS and 67% CO levels. HFCS affected tenderness and aftertaste but not sweetness in cakes formulated with 100% CO. SE emulsified cakes were sweeter than unemulsified or MDG emulsified 100% CO cakes when formulated with 50% and 100% HFCS.     

Sensory and Microbial Quality of Irradiated Crab Meat Products

Low dose gamma irradiation has proved effective in reducing pathogenic and spoilage microorganisms in a variety of seafood products. However, little information is available on the effect of irradiation on the sensory quality and consumer acceptance of such products. We compared microbial and sensory quality of irradiated (2 kGy or less) crab products (white lump, claw, and fingers) through 14-days of ice-storage. Irradiation effectively reduced spoilage bacteria extending shelf-life by more than 3 days beyond control samples. During storage, fresh crab odor and flavor were similar for treated and control samples, while off-flavors and odors developed more rapidly in controls. Overall acceptability scores for irradiated crab samples were higher than for control samples throughout 14-days ice storage.     

基于“三无”食品问题的食品质量监督体系快速构建

目前食品加工行业屡屡出现食品安全问题,食品质量安全监督部门依据相关法律内容及惩罚措施对"三无"食品违法行为打击效果逐步提升。但由于各种原因,食品质量安全监督工作仍存在薄弱环节,食品安全恶性事件仍时有发生。本文列举了2018年4月10日国家抽检食品安全案例,指出基于"三无"食品问题的食品质量监督体系的构建的重要性,以及构建食品监督体系的具体手段。为了保证食品安全,需要加强食品质量监督管理工作,在生产、流通和消费各个领域尽可能地杜绝"三无"食品。     

Using Edible Coating to Enhance Nutritional and Sensory Qualities of Baby Carrots

ABSTRACT: Xanthan gum coating was used to carry 5% Gluconal Cal, a mixture of calcium lactate and gluconate, and 0.2%α-tocopheral acetate (vitamin E) by weight, respectively. Peeled baby carrots were dipped in the coating solutions, dried, and then stored at 2 °C and 85% relative humidity for up to 3 wk. Calcium and vitamin E contents of the coated samples, per serving (85g), increased from 2.6% to 6.6%, and from 0 to about 67% of the Dietary Reference Intakes (DRI) values respectively. Edible coatings (p < 0.05) improved the desirable surface color of carrots without effects (p < 0.05) on the taste, texture, and fresh aroma and flavor except for a slightly slippery surface. The β-carotene level in the baby carrots (p < 0.05) was not affected by edible coating.     

超声辅助低温固态渗透脱水制备茉莉花风味糖浆工艺优化及品质分析

随着中国风味食品和功能饮料市场的不断发展,具有特定营养和健康功效的风味糖浆被用来满足人们对风味饮料的需求。然而目前我国风味糖浆主要采用热浓缩技术进行生产,易导致热敏性芳香物质损失。鉴于此,该研究以茉莉花和黄冰糖为原料,采用超声辅助低温固态渗透脱水方法（Ultrasonic-Assisted Solid Osmotic Dehydration,USOD）制备茉莉花风味糖浆,通过单因素试验确定最佳工艺条件为：黄冰糖用量为茉莉花质量的120%（m/m）、颗粒度为6~20目、渗透时间为168 h及超声时间120 min。在此条件下风味糖浆得率为41.40%;总酚含量、总黄酮含量和DPPH自由基清除能力分别为175.18 mg GAE/kg dw、187.92 mg RE/kg dw和 313.55 mg Trolox/kg dw;茉莉花中绝大部分风味化合物都能被有效地提取出来,尤其是醇类化合物,芳樟醇37.94%~46.06%,其次是苯甲醇20.80%~23.90%,说明SOD工艺条件对风味物质提取影响显著。因此,该研究能有效提高风味糖浆得率且保留了茉莉花本身的风味成分和营养物质,为风味糖浆的开发利用奠定了一定的理论基础。     

Use of Ionizing Radiation to Improve Sensory and Microbial Quality of Fresh-cut Green Onion Leaves

: Fresh‐cut green onion leaves that received γ radiation doses of 0,1,2, and 3 kGy were stored at 3 °C for up to 14 d. Although 2 and 3 kGy of radiation completely eliminated microflora, the treatments frequently resulted in increased loss of aroma and deterioration of visual quality. In addition, radiation caused cellular membrane damage. Samples treated with 1 kGy of radiation had similar or better sensorial quality and a reduced microbial population than the controls throughout the 14 d of storage. Our results suggest that irradiation at a dose of 1 kGy can be used to enhance microbial safety of fresh‐cut green onions without loss in quality attributes.     

Quality Control of Malt: Turbidity Problems of Standard Worts Given by the Presence of Microbial Cells

Since the main effect on beer colour originates from the chemical composition of malt, the measurement of the colour of wort obtained from malt is one of the most important quality parameters to be controlled. Malt colour determination is usually performed spectrophotometrically on EBC Congress worts, which are generally bright. The quality control on the malt harvested in the year 2007 highlighted a problem of turbid Congress wort, for a part of Northern Europe samples analyzed, and therefore the spectrophotometric determination of the colour of wort was not possible. Thus both analytical screening of the quality parameters of malt and the scanning electron microscope (SEM) were used to identify the nature of the turbidity in the worts. The results obtained suggested that the nature of the turbidity of Congress worts could have been due to microbial contamination of the barley, enhanced in particular by the rainy harvest and the consequent formation of exopolysaccharides (EPS) by stressed yeast and bacteria during malting.     

Prediction of the Sensory Quality of Canned Beer as Determined by Oxygen Concentration, Physical Chemistry Contents, and Storage Conditions

ABSTRACT: The objective of this research was to predict any sensory characteristics of canned beer related to its oxygen concentration, composition, temperature, and time intervals of storage. The initial content of oxygen and content of carbon dioxide, pH, color, turbidity, thiobarbituric acid, and bitterness were instrumentally evaluated during 16 wk and 3 storage temperatures. Simultaneously, 8 trained panelists evaluated the degree of oxidation, quality of bitterness, and sensory stability. Principal components regression adjusted models explained the 85% to 86% ( P < 0.01) variability of the sensory characteristics. The results suggest that sensory characteristics of canned beer can be predicted by instrumental measures of its composition and storage conditions.     

Rapid Prediction of Composition and Flavor Quality of Cheddar Cheese Using ATR–FTIR Spectroscopy

ABSTRACT:  Multiple methods are required for analysis of cheese flavor quality and composition. Chromatography and sensory analyses are accurate but laborious, expensive, and time consuming. A rapid and simple instrumental method based on Fourier transform infrared (FTIR) spectroscopy was developed for simultaneous analysis of Cheddar cheese composition and flavor quality. Twelve different Cheddar cheese samples ripened for 67 d were obtained from a commercial cheese manufacturer along with their moisture, pH, salt, fat content, and sensory flavor quality data. Water-soluble components were extracted from the cheese, dried on zinc selenide FTIR crystal and scanned (4000 to 700 cm⁻¹). Infrared spectra of the samples were correlated with their composition and flavor quality data to develop multivariate statistical regression and classification models. The models were validated using an independent set of ten 67-d-old test samples. The infrared spectra of the samples were well defined, highly consistent within each sample and distinct from other samples. The regression models showed excellent fit ( r > 0.92) and could accurately determine moisture, pH, salt, and fat contents as well as the flavor quality rating in less than 20 min. Furthermore, cheeses could also be classified based on their flavor quality (slight acid, whey taint, good cheddar, and so on). The discrimination of the samples was due to organic acids, amino acids, and short chain fatty acids (1800 to 900 cm⁻¹), which are known to contribute significantly to cheese flavor. The results show that this technique can be a rapid, inexpensive, and simple tool for predicting composition and flavor quality of cheese.     

三种碱对水发毛肚感官品质及增重影响的比较

以食品级NaOH、Na2CO3和NaHCO3为材料,进行毛肚水发的单因素试验,分别研究碱液浓度、碱处理时间和反应温度对毛肚感官品质和增重的影响,并将3种碱处理后的毛肚按NY 5268-2004《无公害食品毛肚》的方法进行指标检测,筛选合适的水发用碱。单因素试验结果表明:在感官评价方面,NaOH>Na2CO3>NaHCO3,在增重方面,NaOH具有明显优势。指标检测结果表明:3种毛肚的感官指标、理化指标和微生物指标均达到无公害食品的标准。综合考虑感官品质、增重比、生产周期和性价比,NaOH更适合作为水发毛肚的处理用碱。     

Influence of Storage Atmosphere and Temperature on Quality Evolution of Cut Belgian Endives

ABSTRACT: An optimal combination of O₂, CO₂, and N₂ for storage of cut Belgian Endive was defined, investigating visual quality aspects. In the experimental design, principles of mixture theory were used. The acceptability of cut endives stored under different gas combinations, selected in the range where both CO₂ and O₂ were varied between 2% and 18%, was evaluated by a consumer panel at different time intervals during storage. The response was modeled with a second-degree polynomial, the response surface pointed in the direction of a gas mixture 10% CO₂, 10% O₂, and 80% N₂ for maximum acceptability or best quality during storage. Repeated experiments, including different varieties from 2 different growers, confirmed the optimal gas concentration, (10% CO₂, 10% O₂, and 80% N₂). In a second step, the effect of temperature on quality degradation of cut endives stored under optimal atmosphere conditions, was quantified using the Arrhenius equation. An activation energy of 16.3 kcal/mol was obtained.