果胶制备的研究进展

介绍了果胶的化学结构及其原料，并结合国内外多年的研究成果，综述了果胶的提取、浓缩、沉淀和干燥的方法。     

高粘度聚酯切片特性粘度测试制样方法论证

通过对特性粘度≤1.0高粘切片的特性粘度测试制样方法由压片或研磨改为不压样也不研磨而直接制样测试的可行性进行论证, 最终证实此方法是可行的, 并且能缩短检测时间, 提高检测效率, 减少工作量, 节约检测消耗, 能真正起到及时指导生产、调整和优化产品质量的作用.     

利用微波辅助技术提高柠檬皮果胶提取率的研究

通过对微波辅助技术提高柠檬皮果胶提取率影响的研究，探索了微波处理的最佳工艺参数，即微波输出功率600W，料液比1：3，处理时间58s，处理次数3次，果胶得率与未经处理的样品相比，平均增长率为118.31％。     

高粘切片在锦纶异形丝高速纺中的应用

介绍了用高粘度切片生产锦纶6有光异形全牵伸丝系列新产品的特点及开发过程,并论述了与此相关的设备改造和关键技术。     

用柚子皮提取果胶的工艺优化研究

用柚子皮为原料，通过对水解的酸度（pH）、时间（t）、温度（T）等影响因素的探讨，得出了提取果胶方法的最佳工艺条件。     

共混改性改善高低黏度PET并列复合纤维性能的研究

选取高黏度PET、低黏度PET添加PBT的混合物作为并列纺丝的两种组分进行复合纺丝,并对其可纺性进行研究;采用与不经改性的高低黏度PET并列复合纤维的力学性能对比进行研究。结果表明,高黏度PET/(低黏度PET混合PBT)并列复合纺丝具有良好的可纺性及后加工性能,纺制的复合纤维具有较好的力学性能及自卷曲性能。     

A RESEARCH NOTE: SENSORY QUALITY CHANGES OF HIGH MOISTURE PINEAPPLE BITS DURING STORAGE

Minimally processed high moisture pineapple bits prepared in sucrose syrups, in order to decrease water activity to 0.92, 0.95 and 0.97, were stored at 30, 35 and 40C and evaluated by selected and trained sensory panelists using the Karlsrühe Quality Test. Color, flavor and texture changes were significantly lower for the 0.92 a_w product stored at 30C. It can be predicted by shelf‐life estimation that this product will maintain a satisfactory sensorial and microbiological quality for up to 50 days.     

超高速纺丝吸丝枪吸丝效率影响因素的研究

为了阐明生产条件和纱线规格对吸丝枪吸丝效率的影响,测试了不同纱线种类、纱线喂入速度v和供气压力(表压)p下吸丝枪的吸丝张力F和压缩空气质量流率G,分析了这些因素对吸丝枪吸丝效率η(η=F/G)的影响机理,得到如下结果:p一定时,随着v的增加,F和η减小;v一定时,随着p的增大,F增大,但η下降;相同规格的全牵伸丝(FDY)比拉伸变形丝(DTY)的F和η大;同一种类纱线,线密度越大,F和η越大。研究表明:不同的产品品种和生产条件,应该合理选择吸丝枪并选用合适的供气压力,从而提高生产效率,降低能耗。     

A RESEARCH NOTE: DETECTION OF ADULTERATION IN PROCESSED TRADITIONAL MEAT PRODUCTS

Nondeclared protein addition is one of the most frequent adulterations used in meat products. Meat substitution with an unspecified specie, usually of less quality, is a fraudulent act in the industry and could have economic and health repercussions. In this study, we used an immunodiffusion assay in agar gel to identify bovine, porcine, equine and avion species in two slightly processed meat products, uncooked commercial hamburger and Mexican sausage (chorizo). Analysis of 40 samples from local food stores was performed. Undeclared equine specie was detected in 9 of the 23 of the hamburger meat samples. In Mexican sausage undeclared equine and porcine specie were also found in 5 of the 17 samples. These results showed violations in practices of the regional meat industry. It is suggested that regulatory agencies institute programs to ensure that meat products are properly labeled to protect consumers.     

RESEARCH NOTE : THE USE OF DECOLORIZED BLOOD PROTEIN IN A CHEESE SPREAD

Protein isolates prepared from cattle blood collected at time of slaughter represent a potential source of large quantities of high quality protein. New protein preparations are valued not only for their nutritional benefits but also for their effects on the functional or mechanical properties of foods. A process for decolorizing blood proteins and including them in the manufacture of a white cheese with the body and texture of a cream cheese is described. The experimental cheese appeared to have most of the characteristics of a similar commercial product yet it contained 23.6% more protein.     

INHIBITION OF Staphylococcus Aureus IN A MODEL AGARMEAT SYSTEM BY MONOLAURIN: A RESEARCH NOTE

A sterile agar-meat was acidified with lactic acid and seeded with Staphylococcus aureus. Monolaurin (Lauricidin®), which is a GRAS emulsifier, caused both static and cidal effects on S. aureus 196E. When compared to potassium sorbate, Lauricidin® was slightly more active. The combination of sorbic acid and Lauricidin® (Lauribic™) gave a greater inhibitory effect than either of the substances alone. Inhibitory effects were greater on "anaerobic" than "aerobic" growth. These results indicate that monoglyceride emulsifiers like Lauricidin® alone or in combinations with other preservatives can be used in foods to create environments which are hostile to microorganisms.     

INFLUENCE OF THE INTRINSIC PROPERTIES OF FOOD ON THERMAL INACTTVATION OF SPORES OF NONPROTEOLYTIC CLOSTRIDIUM BOTULINUM: DEVELOPMENT OF A PREDICTIVE MODEL1

The effects and interactions of heating temperature (70–90C), pH (5–6.5), sodium chloride (0–3%), and sodium pyrophosphate (0–0.3%) on the heat resistance of a six strain mixture of spores of nonproteolytic Clostridium botulinum type B and type E in turkey were examined. Thermal death times were determined in submerged vials heated using a water bath. Heated spores were recovered on Reinforced Clostridial Medium (RCM) supplemented with lysozyme (10 μg/ml). Decimal reduction times (D-values) were calculated by fitting a survival model to the data with a curve fitting program. The D-values were analyzed by second order response surface regression for temperature, pH, salt (sodium chloride) and sodium pyrophosphate levels. The four variables interacted to effect the inactivation of spores. Confidence intervals (95%) predicted heat resistance of spores in turkey. The data suggest that the effect of reduced pH in increasing the inactivation was more pronounced at high temperatures and may provide an adequate degree of protection from nonproteolytic C. botulinum spores in minimally processed foods, particularly if employed in conjunction with combinations of salt and sodium pyrophosphate.     

A RESEARCH NOTE: STUDY ON THE QUALITY OF PACHARÁN BY SENSORY EVALUATION

Pachardn is a traditional drink of Navarra, Spain. This spirit is an alcoholic drink which ranges from intense pink to red in color and whose base is sloe (Primus spinosa, L.) flavored with, the essential oils of aniseed and sugar. Sensory analysis was performed using samples from twenty-one different brands of commercial pachardn. Statistical techniques employed were formations of a linear correlation matrix, followed by factor analysis and multiple linear regression. Factor analysis permitted reduction of the sensory variables examined (color, aroma quality, flavor quality, sweetness, acidity and overall impression) to two factor variables (“flavor and aroma” and “color”). The position of the brands with respect to these two factors indicate the necessary changes to improve pachardn quality. The factors “flavor and aroma” had the chief direct effect on Overall Impression.     

A RESEARCH NOTE: ANTIOXIDANT EFFECTS ON COLOR OF AN IRRADIATED BOVINE MYOGLOBIN MODEL SYSTEM

To determine whether antioxidants could protect meat color during irradiation, we extracted myoglobin (Mb) from beef hearts, treated it with one of four antioxidants (control, citric acid [CA], ascorbic acid [AA], ethylenediamine tetraacetic acid [EDTA] or propyl gallate [PG]) and irradiated it at 0.00, 1.25, or 2.50 kGy. The myoglobin model system was then evaluated for pH; Commission Internationale de L'Eclairage (CIE) L *, a * and b * values; hue angle; chroma; and thiobarbituric acid reactive substances (TBARS). Adding CA and AA to the beef myoglobin model system resulted in higher L *, a * and b * values than did EDTA and PG, indicating that these samples were lighter, redder and more yellow. EDTA- and PG-containing samples were more similar to controls containing no antioxidants. Hue angle and chroma supported these findings. Irradiation had no effect on pH, color or TBARS. These results indicate that antioxidants have more influence on beef color than irradiation and that the acidic antioxidants have the potential for preserving color.

PRACTICAL APPLICATIONS

Irradiation has the potential to reduce the microbial load on meat products, producing safer foods for consumers. However, a number of reports have indicated that irradiation can compromise the bright, cherry red color of fresh meat. Off-color will result in consumer rejection of products that may be safe. Antioxidants have the potential to preserve meat color by affecting the state of myoglobin; however, studying these effects in vivo is challenging because of the complexity of the system. In this model system, which was devoid of enzymatic reducing systems and equivalents, the acidic antioxidants, ascorbic acid (AA) and citric acid (CA), were most effective in preserving the color of the pigment. These antioxidants appear to have the greatest potential for preserving fresh meat color during irradiation.     

A RESEARCH NOTE EFFECTS OF AMMONIA EXPOSURE ON FRESH PORK: A DISTINCT PINK COLOR AFTER COOKING

Exposure of raw pork loin chops to ammonia results in the development of a distinct pink color throughout, after cooking to 80C as indicated by visual observations and CIE L*a*b* values. While some of the color development is apparently due to the pH shift caused by the ammonia, experiments suggest that other factors are involved in the formation of the distinct pink color. Samples cooked and then exposed to ammonia failed to develop the pink color. CIE a* values were higher (P < 0.05) for all cooked ammonia treated samples than the cooked control. Distinctly different absorbance spectra (400–700 nm) were observed between cooked, treated samples and either the cooked untreated control, raw fresh pork, or nitrosohemochrome samples. These data suggest that exposure of raw pork to ammonia will influence formation of an undercooked color in fully cooked pork.     

A RESEARCH NOTE: EFFECT OF SUGAR TYPES AND CITRIC ACID CONTENT ON THE QUALITY OF CANNED LYCHEE

The effects of sugar and citric acid content on the color and texture of canned lychee were investigated. For two major cultivar of lychee grown in Taiwan, Hau-yen and No-mitzu, with 0.2% citric acid added to the syrup, the pink discoloration could be reduced and a better texture of lychee flesh maintained if the sugarcontent in the syrup was adjusted nearly to that of the fruit flesh. Among the sugar types tested, sugar mixtures which had the same ratio of sugar types in the syrup as in lychee flesh provided better quality in canned lychee flesh than sucrose alone.     

RESEARCH NOTE: A COMPARISON OF THE CHEMICAL COMPOSITION OF ZANDER (SANDER LUCIOPERCA) LIVING IN DIFFERENT LAKES OF TURKEY

In the present work, the proximate compositions, minerals and trace element contents of zander ( Sander lucioperca ) caught from two lakes (Beyşehir Lake and Seyhan Dam Lake) of Turkey were compared. There were significant differences between moisture and lipid contents, although there were no statistically significant differences between crude protein and ash contents. The mineral and trace elements determined were Na, K, Ca, P, Mg, Zn, Cu, Fe, Pb and Se. Although Na and Fe contents of zanders in two different lakes were different from each other ( P <  0.01), we found no statistically significant differences in terms of Mg, Ca, P, Cu, Pb, Se, Zn contents ( P >  0.01). Among the minerals analyzed, K was the highest followed by P, Ca, Na and Mg. The most abundant trace elements were Zn, Fe, Cu, Se followed by Pb, and these elements were below the limits proposed by Turkish Food Codes for human consumption in the meat of zander.

PRACTICAL APPLICATIONS

This present study includes information about the nutritional value of zander, which lives in the fresh water lakes of our country and of which people are fond and is being exported. The comparison of the proximate, mineral and trace element contents of the same species which are caught in two different lakes has been made. In the scope of human nutrition, in accordance with the minerals which have got much importance, it involves useful information about what the position of this fish is, and whether it contains any risk due to trace elements. Furthermore, concerning this subject, it will also light the way for studies to be made in the future.     

A RESEARCH NOTE: EFFECT OF CITRIC ACID AND/OR ROSEMARY EXTRACT ON COLOR OF AN IRRADIATED BEEF MYOGLOBIN MODEL SYSTEM

To determine the effect of antioxidants and irradiation on meat color, myoglobin (Mb) was extracted from beef hearts. Mb was treated with one of four antioxidants (control, citric acid [CA], rosemary extract [RE] or combination of citric acid and rosemary extract [CA/RE]) and irradiated at 0.00 (Control), 0.50, 0.75, 1.00, 1.25, 1.50, 1.75 and 2.00 kGy. Samples were then evaluated for thiobarbituric reactive substances, pH, L*, a* and b* values, hue angles, and Chroma. RE- and CA-containing samples had the highest postirradiation L*, a* and b* values, indicating they were lighter, redder and more yellow than controls. In terms of hue angles, all samples treated with antioxidants were much closer to the true red axis ( a* =  0) of the CIE color space, both before and after irradiation, than was the control . The only color attribute affected by irradiation dose was L* value. Samples irradiated at 2.0 kGy were significantly lighter ( L* =  5.27) than samples that had not been irradiated ( L* =  1.28).

PRACTICAL APPLICATIONS

Irradiation is an effect method for extending the shelf life and improving the safety of fresh meat products; however, it can cause undesirable color changes at the surface of the meat, which appear to be the result of oxidative processes – therefore, reducing oxidation could effectively reduce color change. Studying pigment preservation is difficult in intact muscle tissue, so a myoglobin model system was developed for this purpose. Natural antioxidants were evaluated in this system. Rosemary extract and citric acid maintained color lightness and redness. Surface application of these antioxidants has the potential to preserve red meat color during irradiation.