DIPHENYLAMINE RESIDUES IN APPLES AND APPLE CIDER

Diphenylamine (DPA) is an antioxidant which is widely used on apples for scald control during fruit storage. Since appreciable residues of DPA remain on apples when sold, it was of interest to study the extent of possible transfer of the compound to cider. Cider was expressed from five cultivars ofDPA-treated apples following their storage and the original fruit, the pomace and cider was analyzed for DPA residues. Only traces of the compound were found in cider with virtually all of the DPA found concentrated in the pomace. The toxicologic significance of the results are discussed.     

STORAGE QUALITY OF PASTEURIZED AND UV TREATED APPLE CIDER

Two studies were conducted to assess the effect of hot-fill pasteurization at 63C and UV irradiation at 14 mJ/cm² on the quality and shelf-life of apple cider packaged under controlled conditions with minimal packaging contamination, and under pilot plant conditions resembling commercial operations. The processed cider was stored at 7C for up to 14 weeks in the first study and 4 weeks in the second. Microbiological, chemical and sensory tests were conducted weekly on cider samples. There were no significant differences among the fresh processed ciders with regard to taste and preference. All treatments achieved a reasonable reduction in microbial counts, although hot-fill pasteurization provided longer shelf-life. There were significant changes in pH, titratable acidity, soluble solids and turbidity of samples during storage. Hot-fill at 63C is a comparable alternative to flash pasteurization at 71C for 6 s for the production of safe quality cider at small cider mills.     

UV INACTIVATION OF E. COLI O157:H7 IN APPLE CIDER: QUALITY, SENSORY AND SHELF-LIFE ANALYSIS

Increasing concern about food safety following contamination of unpasteurized apple cider with Escherichia coli O157:H7 reinforces the need for using the best technologies in apple cider production. Pasteurization of apple cider with ultraviolet irradiation (UV) is a low‐cost alternative to heat pasteurization for small processing operations. UV treatment efficacy applied to raw unpasteurized apple cider was examined through evaluation of physical parameters, exposure time and treatment dosage. A UV light processing system was used to treat apple cider. The apple cider received a calculated average dosage of 8777 µW‐s/cm ² per pass through the system. UV light (at 254.7 nm) was effective in reducing bacteria‐inoculated apple cider by an average of 2.20 logs per pass. In multiple passes, the 5‐log reduction mandated by the Food and Drug Administration was achieved. Sensory analysis yielded no significant differences between the UV‐treated and control apple ciders. Experiments with UV‐treated apple cider indicated a significant extension of product shelf life through inhibition of yeast and mold growth. For low throughput apple cider processing operations, this technology is a viable cost‐effective alternative.     

INACTIVATION OF E. COLI 0157:H7 IN APPLE CIDER BY OZONE AT VARIOUS TEMPERATURES AND CONCENTRATIONS

The effect of temperature (5–20C) at 860 ppm (v/v) ozone and different gaseous ozone concentrations above 1,000 ppm on inactivation of E. coli O157:H7 in apple cider was studied. Lag times ranged from 3.5 min at 20C to 6.7 min at 10C before the on-set of E. coli O157:H7 inactivation. D-values ranged from 0.6 to 1.5 min at 20C and 5C, respectively. After ozone treatment of cider for 14 min, dissipation of ozone from cider was slow, decreasing to about 5 mg/L after 2 h at 5C. At high gaseous ozone concentration, log time was shortest and D-value lowest. There was a critical concentration of dissolved ozone of about 5–6 mg/L at 20C, before the on-set of E. coli O157:H7 inactivation in the cider. Total processing times, based on lag time plus 5D, ranged from about 4 to 14 min depending on temperature and ozone concentration. Overall, inactivation of E. coli O157:H7 by ozone was fast enough to allow practical applications in cider production, and it should be considered as an alternative to thermal pasteurization.     

HEAT INACTIVATION OF ESCHERICHIA COLI 0157:H7 IN APPLE CIDER IN THE PRESENCE OF GLYCEROL MONOLAURATE AND A SYNTHETIC ANTIMICROBIAL PEPTIDE, PR-26

The effect of moderate temperatures in combination with glycerol monolaurate and an antimicrobial peptide, PR-26 on E. coli 0157:H7 in apple cider was determined. A five-strain mixture of E. coli 0157:H7 was inoculated into apple cider (pH 3.53) containing 0.01% PR-26 or 0.02% glycerol monolaurate or a combination of 0.01% PR-26 and 0.02% glycerol monolaurate. The apple cider was incubated at 40, 45 or 50C for 30 s, 5 min, 10 min, and 15 min. At each of the specified time intervals, the surviving population of E. coli 0157:H7 was determined. At all the three temperatures, there was no significant difference (P > 0.05) between the E. coli 0157:H7 populations of the control and the treatment containing PR-26. However, the treatments containing glycerol monolaurate alone or combination of glycerol monolaurate and PR-26 resulted in significant reductions (P < 0.05) in E. coli 0157:H7 counts. Results indicate that addition of glycerol monolaurate (0.02%) to apple cider and heating at 50C for 5 min can reduce E. coli 0157:H7 by 5.0 log CFU/mL.     

THE EFFECTS OF THERMAL AND NONTHERMAL PROCESSING METHODS ON APPLE CIDER QUALITY AND CONSUMER ACCEPTABILITY

Due to increased concern about the safety of fruit, vegetable and juice products, the FDA has mandated that these must undergo a 5‐log reduction in pathogens. The development of various processing methods for juice products has caused the need to determine the effects of these methods on said products. The effect of thermal pasteurization, UV irradiation and ozone treatment on apple cider quality and consumer acceptability was studied over 21 days. Thermally pasteurized samples were different in color and less preferred in all areas of consumer acceptability. UV‐irradiated samples were lower in soluble solids for the first 7 days and showed no significant difference in consumer acceptability. Ozone‐treated cider had greater sedimentation, lower sucrose content and a decrease in soluble solids by day 21. UV irradiation allows for a more cost‐effective method to produce safe apple cider with minimal quality and consumer acceptability differences.     

YEAST STRAIN AND THE FORMATION OF FLAVOUR COMPONENTS IN CIDER

Two apple juices were fermented at 8°C and 18°C using thirteen strains of Saccharomyces uvarum. Glucose, fructose, malic, lactic, isobutanol, 2–3 butanediol, isoamyl alcohol, ethyl acetate and titratable acidity were determined in the two resulting experimental ciders. This data was correlated by means of multiple regression equations derived from earlier work with the following organoleptic characteristics: sweetness, sourness, fruity, scented, sharp and irritating flavours and a “global hedonic score” for overall acceptability. A significant effect of yeast strain could be detected on all component concentrations except ethanol, ethyl acetate, amyl alcohols and titratable acidity. The amounts of malic acid and titratable acidity found in cider depends mainly on the source of the juice. The anticipated effect of the source of the juice on sourness and on sharpness and fruity flavours is therefore significant. Yeast strain is also expected to have a significant effect on fruity and sharp flavours as well as on overall acceptability.     

CLONAL HERBAL EXTRACTS AS ELICITORS OF PHENOLIC SYNTHESIS IN DARK-GERMINATED MUNGBEANS FOR IMPROVING NUTRITIONAL VALUE WITH IMPLICATIONS FOR FOOD SAFETY

Plant phenolics are secondary metabolites that confer beneficial properties to the plants that produce them. Extracts made from plants that produce these phytochemicals are increasingly being recognized for their antimicrobial properties. In this study, we investigated extracts made from high‐phenolics‐producing clonal lines of oregano and thyme for potential as elicitors of phenolic antioxidant production in dark‐germinated mungbean (Vigna radiata,). Mungbean was dark‐germinated under the rationale that any energy stored in the bean seed in the form of starch may potentially be utilized for enhanced phenolics production, since without a light source the dark‐germinated seedling may not stimulate the development of photosynthetic components. Wafer‐based herb extracts showed the greatest ability to stimulate phenolic content in dark‐germinated mungbeans. Three of the oregano extracts were investigated further and showed an ability to stimulate glucose‐6‐phosphate dehydrogenase (G6PDH), guaiacol peroxidase (GPX), and antioxidant activity. These results suggest that the extracts contain an active elicitor that stimulates phenolic antioxidant content, as well as activity of the pentose‐phosphate pathway. In addition, the results of this study suggest that extracts of high‐phenolics‐producing clonal plants may have potential in the food and agriculture industry as seed treatments for preventing bacterial infection in germinating sprouts by stimulating phenolic antioxidant‐producing pathways, as well as for increasing the nutritional value of sprouts for human consumption.     

THE INFLUENCE OF MICROWAVES AND SELECTED MANUFACTURING PARAMETERS ON APPLE CHIP QUALITY AND ANTIOXIDANT ACTIVITY

Apple chips belong to the group of low-processed food products and are an interesting alternative to currently popular snacks. The aim of the work was to estimate the influence of chosen technological parameters on quality and antioxidant properties of apple chips. Thickness of apple slices, drying temperature and initial microwave treatment were analyzed.
On the basis of experimental data, it was established that the drying temperature of 90C was optimal for obtaining products with advantageous sensory value. Apples before drying should be cut into slices 3.5 mm thick and immediately soaked in a solution containing saccharose, apple concentrate, citric acid and SO₂. It was shown that microwave pretreatment of apple slices (150–300 W, 5–10 min) shortened the drying time by about 25% and increased the antioxidant potential by about 30%.

PRACTICAL APPLICATIONS

Because of the increasing incidence of civilization diseases, worldwide interest in snack products that are low in calories and healthy is still growing. The optimum parameters of apple chip production (slice thickness and drying temperature) to obtain a product of high antioxidant potential are presented in this study. It is also shown that application of microwave pretreatment enabled us to shorten the process duration and to reduce the production costs while antioxidant activity remained at a relatively high level.     

THE PERMEABILITY OF THE SURFACE LAYERS OF CEREAL GRAINS,AND IMPLICATIONS FOR TESTS OF ABRASION IN BARLEY

The husk of barley, and the pericarps of naked, husked and ‘stripped’ barleys, of wheat and rye are more or less permeable to aqueous solutions of salts, or Eosin. The pericarps of stripped barley grains conduct aqueous solutions so that, for example, they conduct solutions of Eosin, or [¹⁴C]-gibberellic acid from the apex to the base of the grain where it accumulates in the embryo region. On the other hand the husk and pericarp are not so readily permeated by aqueous Trypan Blue. The testa/nucellar cuticle, together with the pigment strand, limits the inward penetration of salts and dyes. Gibberellic acid, and apparently water also, traversed the testae of some, but not all, decorticated barley grains, as demonstrated by the consequent modification of the starchy endosperms. However in most instances gibberellic acid solution does not traverse the surface layers of stripped grains and induce modification in their endosperms.     

国内外食品安全卫生标准状况的比较研究

通过比较我国食品安全卫生标准和国外先进国家相关标准的差异，研究明确我国食品存在问题的原因。     

DISCOVERY OF THE “CIDER SICKNESS” BACTERIUM ZYMOMONAS ANAEROBIA IN APPLE PULP

After a lapse of nearly 20 years the “cider sickness” organism has been rediscovered. On this occasion it was found in apple pulp, this being the first time it has been isolated from a source other than “sick cider”. In spite of its presence in the pulp, no outbreak of the disorder occurred in the factory from which it was isolated, thus reaffirming the soundness of the cider-making methods specifically designed to prevent the growth of this bacterium. The characteristics of this isolate are compared with the two known species, namely, Zymomonas anaerobla and Z. mobilis and it is concluded that the new isolate is a strain of the former.     

YEAST STRAIN AND KINETIC ASPECTS OF THE FORMATION OF FLAVOUR COMPONENTS IN CIDER

An apple juice was fermented at 8°C using twelve strains of Saccharomyces uvarum. Glucose, fructose, malic and L-lactic acids, isobutanol, 2,3 butanediol, isoamyl alcohol, ethyl acetate and titratable acidity were determined and monitored in the course of fermentation. It was observed that yeast strains differed from one another mainly in fermentation rates. When components were determined in ciders of the same remaining fructose concentration, rather than after the same fermentation time, the only significant effect of the yeast strain was on the amounts of glucose and ethanol in sweeter cider (fructose 34 g/litre), or on the amounts of glucose, acetic acid, isobutanol and amyl alcohols in dryer ciders (fructose 17 g/litre). A sensory analysis showed that standard deviations of concentrations of remaining or formed components in ciders fermented by different yeast strains, was sufficient to be detected by the taste panel. Added glucose in this range of concentration (1.5 g/litre) in cider reduced the perception of sourness while the addition of acetic acid (0.3 g/litre) reduced the perception of the scented flavour. Added Isobutnol (6 mg/litre) reduced the perception of sweetness. No significant effect of added isoamyl alcohol (30 mg/litre) could be detected. Chemical determinations were correlated by means of regression equations derived from earlier work with some organoleptic characteristics. No anticipated effect of the yeast strain could be detected on any studied flavour characteristic. It is concluded that in ciders of the same attenuation, the effect if it does exist, of the S.uvarum strain isolated from ciders, must be low.     

大孔吸附树脂对苹果渣中苹果多酚吸附性能的研究

研究了8种大孔吸附树脂对苹果渣中苹果多酚的吸附与解吸性能,其中AB-8、NKA、X-5、D4006树脂具有较大吸附量和解吸率,其静态吸附量:AB-8>X-5>D4006>NKA,解吸附率:X-5>NKA>AB-8>D4006,吸附速率:AB-8>X-5>NKA>D4006,从中选出AB-8树脂对苹果多酚进行纯化。动态吸附实验研究了提取液浓度、pH、流速对AB-8树脂吸附量的影响,适合的上柱浓度为1.1528mg/mL,pH为4.80,吸附流速为2BV/h,4倍树脂床体积的70%乙醇以1BV/h的流速进行洗脱即可基本将苹果多酚从AB-8树脂上解吸下来。     

SHELF-LIFE OF FRESH FILLED PASTA. HAZARD ANALYSIS AND CRITICAL CONTROL POINTS OF THE MANUFACTURING PROCESS AND HOUSEHOLD PRACTICES

Hazard Analysis and Critical Control Point (HACCP) approach was used to assess the safety of a fresh filling pasta (ricotta-filled ravioli) manufacturing plant in La Plata region, Argentina. Household practices like cooking and holding meals before serving were also evaluated. Samples of ricotta, main raw material of the filling, showed colony counts of Enterobacteriaceae total microorganisms, molds and yeasts of (5 × 10³-1 × 10⁵), (1x10⁵−1x10⁸) and 1 × 10⁵ CFU/g, respectively. E. coli was also detected in one out of five samples, suggesting a hazardous condition of this raw material. Salmonella spp. was not isolated from any of the dough samples tested. Ricotta filling showed high colony counts of mesophilic microorganisms (6 × 10⁶ CFU/g), Enterobacteriaceae (1 × 10⁵ - 1 × 10⁶ CFU/g), while E. Coli was detected in 20% of the samples. Counts of B. cereus, S. aureus were less than 1 × 10² CFU/g in the analyzed materials. In the finished product (ricotta-filled ravioli), the colony counts of mesophilic microorganisms and Enterobacteriaceae were 3 × 10⁸ and 8 × 10⁵ CFU/g, respectively. Critical Control Points found were cooking and holding time before serving. The implementation of suggested corrections allowed the microbial quality of the final product (ricotta-filled ravioli) to be improved considerably. The growth of total microbial counts during refrigerated storage (0, 4, 8 and 10C) were measured and the shelf-life of ricotta and ricotta-filled ravioli was calculated.     

LACTIC ACID BACTERIA AND MALOLACTIC FERMENTATION IN THE MANUFACTURE OF SPANISH CIDER

Numeration, isolation and identification of the lactic acid bacteria found in Asturian cider during processing and storage has been carried out. The species Leuconostoc oenos was predominant during both alcoholic and malolactic fermentations. In most of the ciders studied the malolactic fermentation and the alcoholic fermentation started at the same time; production of D-lactate as well as a decrease of L-lactate were to be found once the malolactic fermentation was complete .     

金刚石的异常双折射特征及其意义

金刚石异常双折射的不同形式和组合是生长应力和生长期后应力作用的结果,利用偏光显微镜观察已加工成薄片的金刚石,可以了解金铡石的生长期次和塑性变形的特点,金刚石异常双折射的成因分析为5种,对硝南金刚石的正交偏光特征进行分析,认为正交偏光研究是阴极发光（CL）揭示金刚石生长多期性的有益补充,反映生长期后塑性变形,内应力等方面的信息化CL图丰富,比拉曼光谱直观。