DETERMINATION OF ORTHO-NASAL AROMA THRESHOLD FOR MULTICOLORED ASIAN LADY BEETLE IN A CONCORD GRAPE JUICE

ABSTRACT

Sensory evaluation was used to determine the aroma threshold of Harmonia axyridis (multicolored Asian lady beetle [MALB]) in Concord grape juice. Prior to Concord grape juice preparation, MALB was added to the Concord grapes at concentrations of 0 and 8.4 MALB/kg fresh grapes. To determine the odor threshold, the three alternative forced‐choice method of sample presentation was used, with an ascending concentration series of 0.5, 1.5 and 4.5 MALB/kg fresh grapes. The panel aroma threshold concentration, calculated using the best estimate threshold over two panel sessions, was 1.8 MALB/kg fresh grapes. Individual detection thresholds ranged from 0.29 to 7.79 MALB/kg fresh grapes, with 75% of the panelists having a detection threshold at or below 0.87 MALB/kg fresh grapes. These results indicate the influence of low numbers of MALB on Concord grape juice aroma, and suggest the importance of quality control programs, including the implementation of established tolerance limits, to monitor grape quality.

PRACTICAL APPLICATIONS

Harmonia axyridis, the multicolored Asian Ladybeetle (MALB), was originally introduced as a method of biocontrol. However, its presence is now becoming problematic with respect to crop quality. In order to minimize economic losses to the Concord grape industry, determination of the number of MALB required to produce a detectable change in Concord grape juice is critical for juice producers in the establishment of their quality control programs. Therefore, the objective of this study was to determine the aroma threshold level of MALB in Concord grape juice. The panel aroma threshold concentration, calculated using the best estimate threshold was 1.8 MALB/kg fresh grapes, with 75% of the panelists having a detection threshold at or below 0.87 MALB/kg fresh grapes. These results indicate the influence of low numbers of MALB on Concord grape juice aroma, and suggest the importance of quality control programs, including the implementation of established tolerance limits, to monitor grape quality.

     

Announcing new books in material science

Announcing new books in material science     

Vascular function in berries of Vitis vinifera (L) cv. Shiraz

Anatomical studies on the movement of a xylem tracer dye were combined with functional studies on changes in grape berry volume during final stages of berry ripening to gauge xylem effectiveness. Movement of a xylem tracer dye into pre-veraison fruit was compared with movement into post-veraison fruit by feeding a solution of acid fuchsin to excised shoots with bunches still attached, and then sectioning fruit for photo-microscopy. Those comparisons confirmed published studies showing an apparent blockage to dye movement along major vessels within the brush tissue of post-veraison fruit. However, our functional approach yielded a different impression of vascular activity. A continuation of xylem transport in ripening fruit was inferred from comparisons of berry volume where pedicels were either girdled (phloem interrupted, but xylem intact) or excised (both phloem and xylem interrupted). Volume changes in manipulated berries were compared with immediately adjacent intact control berries within the same bunch. Control fruit lost volume subsequent to 78 days after flowering (DAF) while manipulated fruit lost volume from the first day of treatment at 67 DAF. By harvest time at 95 DAF, both control fruit and girdled fruit had fallen to 91% and excised fruit to 46% of maximum volumes recorded around 78 DAF. Berry volume loss in girdled fruit was further enhanced by deficit irrigation. We conclude that xylem flow into those Shiraz berries must have continued beyond veraison despite dye evidence of a vessel blockage within the brush region of analogous post-veraison fruit.     

Exclusion of sunlight from Shiraz grapes alters wine colour, tannin and sensory properties

The aim of this study was to determine how changes in grape composition brought about by artificial shading (sunlight exclusion) influence wine properties including colour, flavonoid composition and sensory attributes. Prior to flowering, bunches of Shiraz grapes were enclosed in boxes designed to eliminate light without altering bunch temperature and humidity. This artificial bunch shading had little effect on berry ripening and accumulation of sugar but at harvest the shaded bunches had smaller berries and higher seed weight, juice pH and titratable acidity. The amount of anthocyanins in the fruit was not changed significantly but anthocyanin composition in the shaded berries was shifted towards dioxygenated anthocyanins (the glucosides of cyanidin and peonidin derivatives). Shaded fruit had increased seed tannins and decreased skin tannins but the largest relative change in flavonoids was a marked decrease in flavonols in the shaded fruit, similar to previous studies. Wines made from shaded fruit had lower wine colour density, total phenolics, anthocyanins and tannins when the wine was bottled and after ageing for up to three years. Analysis of potential flavour compounds following acid hydrolysis indicated that the wines made from shaded fruit had decreased levels of glycosides of β-damascenone and 1,1,6-trimethyl-1,2-dihydronaphthalene (TDN). Sensory analysis of the wines indicated no significant difference in aroma attributes but the wines made from shaded fruit were rated lower for astringency, fruit flavour and flavour persistence in-mouth sensory attributes. The results indicate that extreme shading of Shiraz fruit can decrease wine colour, anthocyanins and tannins as well as altering sensory attributes.     

ACCEPTABILITY OF VARIOUS GROUND BEEF AND PORK PRODUCTS EXTENDED WITH MECHANICALLY SEPARATED BEEF

Six blends of ground beef and six blends of ground pork containing 0, 15, 30, 45, 60 or 75% mechanically separated beef (MSB) were prepared. Also five batches of fermented sausage and spiced luncheon loaf containing 0, 5, 10, 15 and 20% MSB were formulated. Level of MSB was not related to juiciness rating or mealiness scores of cooked beef/MSB or pork/MSB patties. The level of MSB significantly affected overall eating satisfaction ratings for each blend of MSB patties. MSB at levels of 15% or more had a negative effect on flavor acceptability of cooked ground beef or pork. Fermented sausage products could be extended with only 5% MSB without creating defects in visual appearance or sensory properties. However, the inclusion of 20% MSB yielded a spiced luncheon loaf which was higher in eating quality than an all-beef control. The beef/MSB patties, fermented sausage, and spiced luncheon loaves containing 15% MSB were acceptable for visual appearance. Based on this study, MSB produced from a press type machine, can be blended up to 15% with ground beef, ground pork and sausage products without significantly decreasing raw appearance, sensory properties or storage life. Since MSB is a red meat product available at a similar low cost as textured vegetable protein, the red meat industry would benefit from expanded use of this high protein extender.     

新型传感器在遥控激光焊接技术中的应用

新型激光器（纤维或盘形激光器）的光束质量的不断提高和新的CO2激光发射系统技术是促进激光材料加工发展的基础。这种激光技术在汽车制造业开拓了新的应用领域：采用扫描技术的遥控焊接。为提高应用激光技术的收益，例如，在系列化生产中，生产过程需要自动化质量控制？     

WORKPLACE RESTRUCTURING AND URBAN FORM: THE CHANGING NATIONAL SETTLEMENT PATTERNS OF THE CANADIAN WORKFORCE

ABSTRACT:  This article examines the relationship between emerging work arrangements and national settlement patterns. While growth is centralized in large cities, social commentators continue to suggest that workplace restructuring—facilitated by technological progress—encourages more dispersed settlement patterns, evoking concern about the environmental sustainability of the trend. Multivariate analysis using Canadian census data shows that with the exception of self-employed professionals, the home workers, and self-employed in nonmanual occupations have a lower tendency to reside in large cities than otherwise similar wage and salary earning commuters. However, household mobility and temporal trends suggest that workplace restructuring is not dispersing workers away from large cities by inducing mobility, but that take-up is higher in more remote areas. It is argued that workplace restructuring permits more dispersed national settlement patterns than if workers needed to move to large cities for proximity to employment growth. The article reflects on the implications of the findings for urban sustainability policies that promote compact urban forms and the policies that emphasize consumption amenities of cities to attract mobile workers.     

Reproductive growth of grapevines in response to nitrogen supply and rootstock

Nitrogen fertiliser was applied at two rates (0 or 100 kg N/ha) to field-grown Müller-Thurgau grapevines grafted onto six rootstocks (Kober 5BB, Teleki 5C, Teleki 8B, Selection Oppenheim 4, Couderc 3309, Ruggeri 140). Half the nitrogen was applied four weeks pre-flowering and half at the end of flowering. Nitrogen supply reduced symptoms of inflorescence necrosis and improved fruit set, but increased bunch-stem necrosis, Botrytis cinerea bunch rot and yield. This was associated with reduced grape sugar, higher acidity and lower pH. Rootstocks had no significant effect on inflorescence necrosis, bunch-stem necrosis and bunch rot, but vines grafted on C-3309 and Ru-140 had both lowest yields and highest fruit quality. Nitrogen × rootstock interactions were rare and contributed little to total variance, suggesting that rootstock-induced differences in scion performance were, except for SO4, largely independent of soil nitrogen level.     

The effect of Saccharomyces cerevisiae and Saccharomyces bayanus yeast on colour properties and pigment profiles of a Cabernet Sauvignon red wine

Red wine was made from the same batch of Cabernet Sauvignon grapes but with two different yeasts, Saccharomyces cerevisiae (SC) or Saccharomyces bayanus (SB). The colour properties and pigment profiles of SC and SB wines were compared at 8 days and 387 days after yeast inoculation. Grape anthocyanin concentration was found to be lower in SB wines than in SC wines at day 8 and 387, but SB wine exhibited greater wine colour density, a* and b*. The anthocyanin concentration did not correlate with wine colour density. The levels of pigmented polymers and SO₂ non-bleachable pigments were found to be higher in SB wine at day 387, demonstrating that the formation of stable pyranoanthocyanins and pigmented polymers was enhanced by SB yeast. Electrospray mass spectrometry was used for the compositional analysis of pyranoanthocyanins, and direct and ethyl-bridged linked condensation dimers of malvidin 3- O -glucoside (MvG) with flavanols (catechin or epicatechin). The data demonstrated that the formation of acetaldehyde-mediated pigments was enhanced by the use of the SB yeast. The compositional analysis suggested that the differences in colour properties and pigment profiles of SC and SB wines were largely due to the greater production of acetaldehyde-mediated pigments by the use of SB yeast.     

ACCEPTABILITY OF BEEF PATTIES EXTENDED WITH PORK AND/OR TEXTURED SOY PROTEIN1

Four beef or beef/pork ground meat blends were extended with textured soy protein (TSP) at 0, 10, 20 and 30% levels. Ground beef/pork/textured soy protein (TSP) patties with 30% TSP were rated lowest by consumers for raw color and appearance and overall cooked appearance. A beef (50%) and pork (30%) blend containing no TSP was rated highest by consumers for tenderness, flavor and overall desirability and higher by a trained sensory panel for flavor and overall desirability than blends containing TSP. Overall desirability ratings for visual and palatability characteristics of beef/pork meat patties were higher than for beef/pork/TSP blends. Results indicated a distinct advantage for palatability of the beef/pork blend as compared to beef/pork/TSP combinations.