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Notes: The object of this study was to determine the effect of closing date and date of harvest for conservation (accumulation period), on dry-matter (DM) yield and forage quality of annual pasture in Western Australia. The field study comprised 48 plots, 2 m × 2 m, sown with either annual ryegrass (Lolium rigidum Gaud.) or Italian ryegrass (L. multiflorum Lam.), and mixed with subterranean clover (Trifolium subterraneum L.). Defoliation of swards until the end of winter was at the three leaves tiller–1 stage. In spring, once stem nodal development had commenced, swards were defoliated every 3–4 weeks. Swards were defoliated either twice with three leaves tiller–1 (accumulation period 1 commenced on 15 August); twice with three leaves tiller–1 and then once after 4 weeks (accumulation period 2 commenced on 11 September); twice with three leaves tiller–1 and then twice after 4-week intervals (accumulation period 3 commenced on 9 October) or; twice with 3 leaves tiller–1 and then twice after 4-week intervals and then once after 3 weeks (accumulation period 4 commenced on 30 October). From the commencement of the accumulation period, tiller density, DM yield and forage quality were determined weekly for up to 10 weeks.There was a positive quadratic association between DM yield and days after the commencement of the accumulation period. Yields were maximized from accumulation period 1 with 5·3, 6·6 and 9·5 t DM ha–1, and growth rates were 140, 128 and 145 kg DM ha–1 d–1, for Wimmera annual ryegrass and Richmond and Concord cultivars of Italian ryegrass respectively. In contrast, in vitro dry-matter digestibility (IVDMD) and crude protein (CP) content were negatively associated with days after the commencement of the accumulation period, and initial values were greater than 0·80 and 180 g kg DM–1 for IVDMD and CP content respectively. The rate of decline in IVDMD d–1 for Wimmera annual ryegrass was 0·005, 0·019 and 0·012 d–1 for accumulation periods 1, 2 and 3, respectively, while for Italian ryegrass cultivars Richmond was 0·015, 0·011, 0·02 and 0·012 d–1 and Concord was 0·014, 0·009, 0·013 and 0·01 d–1, for the 4 accumulation periods respectively.It is recommended that annual and Italian ryegrass pastures be harvested between 10% and 20% inflorescence emergence when IVDMD will exceed 0·70 regardless of cultivar and/or defoliation practice prior to the commencement of the accumulation period.

Notes: The effect of defoliation on the vegetative, early reproductive and inflorescence stages of tiller development, changes in the dry-matter yield of leaf, stem and inflorescence and the associated changes in forage quality was determined on plants of annual ryegrass (Lolium rigidum Gaud.) and Italian ryegrass (L. multiflorum Lam.). The field study comprised seventy-two plots of 1 m × 2 m, sown with one annual ryegrass and seven Italian ryegrass cultivars with a range of heading dates from early to late; defoliation commenced 6 weeks after germination. During the vegetative stage of growth, plots were defoliated when the tillers had three fully expanded leaves (three-leaf stage). During the early reproductive stage of growth, to simulate a cut for silage, plots were defoliated 6–7 weeks after 0·10 of the tillers displayed nodal development. The subsequent regrowth was defoliated every 3 weeks.Assessments of changes in tiller density, yield and quality were made in the growth cycle that followed three contrasting cutting treatments during the winter–spring period (from 10 July). In treatment 1, this growth cycle (following closing-up before a subsequent conservation cut) commenced on 7 August following two defoliations each taken when the tillers were at the three-leaf stage. In treatment 2, the growth cycle commenced on 16 October following: for early-maturing cultivars, two cuts at the three-leaf stage, a cut for silage and an additional regrowth cut; for medium-maturing cultivars three cuts at the three-leaf stage and a cut for silage; and late-maturing cultivars, five cuts at the three-leaf stage. In treatment 3, defoliation up to 16 October was as for treatment 2, but the growth cycle studied started on 27 November following two additional regrowth cuts for early- and medium-maturing cultivars and cut for silage for the late-maturing cultivars.Tiller development for all cultivars was classified into three stages; vegetative, early reproductive and inflorescence. In treatment 1, in vitro dry-matter digestibility (IVDMD) and crude protein (CP) content were negatively associated with maturation of tillers. IVDMD ranged from 0·85 to 0·60 and CP ranged from 200 to less than 100 g kg–1 dry matter (DM) during the vegetative and inflorescence stages respectively. This large reduction in forage quality was due to an increase in the proportion of stem, inflorescence and dead material, combined with a reduction in the IVDMD and CP content of the stem. A high level of forage quality was retained for longer with later-maturing cultivars, and/or when vegetative tillers were initiated from the defoliation of early reproductive tillers (treatments 2 and 3). However, 15 weeks after the closing-up date in treatment 1, defoliation significantly reduced the density of inflorescences with means (±pooled s.e_m.) of 1560, 1178 and 299 ± 108 tillers m–2, and DM yield of inflorescence with means of 3·0, 0·6 and 0·1 ± 0·15 t ha–1 for treatments 1, 2 and 3 respectively.This study supports the recommendation that annual and Italian ryegrass cultivars should be classified according to maturity date based on the onset of inflorescence emergence, and that the judicious defoliation of early reproductive tillers can be used to promote the initiation of new vegetative tillers which in turn will retain forage quality for longer.

Notes: Commercial samples of white pan bread were evaluated by instrumental and sensory methods to determine the relationship between sensory and instrumental assessments, and relate them to product quality. Samples were evaluated on days 4 and 12 after baking. Sensory analysis was carried out by a panel of ten assessors trained in descriptive analysis of bread texture. A Texture Profile Analysis (TPA) was carried out using a TA.-XT2 Texture Analyzer. Collected data was statistically analyzed by Three-Factor Analysis of Variance, Principal Component Analysis, and Linear Partial Least Squares Regression Analysis (PLS). PLS revealed that sensory texture could be well predicted by instrumental texture measurements. It can be concluded that the evaluation of a few sensory manual texture parameters can be used as a tool to establish specifications for quality control programs.

Notes: : Survival analysis concepts to be used in sensory shelf life studies were introduced, together with the equations necessary for calculations. The survival function was defined as the probability of consumers accepting a product beyond a certain storage time. Censoring phenomena, a key concept in survival analysis, was defined and has been shown to occur in sensory shelf-life data. Concepts and calculations were applied to a data set obtained from 50 consumers who each tasted seven yogurt samples with different storage times, answering “yes” or “no” to whether they would consume the samples. From this censored data set, nonparametric and parametric models were obtained that allowed shelf-life estimations.

Notes: Mayonnaise is microbiologically stable, thus its shelf-life is determined by the change in its sensory properties, mainly flavor changes due to oxidative rancidity of its main component, oil. The effect of storage temperature, fat content and type of package on the shelf-life of a commercial mayonnaise was studied. Sensory descriptors with corresponding references are presented. The sensory descriptors which varied with storage time were: total aroma, and for flavor: egg, oily and oxidized. Rate of oxidized flavor change was greater in whole fat than in low fat mayonnaise. For 10 cm3 pouches, package related flavors were developed during storage. Shelf-life ± confidence interval for whole fat mayonnaise was 184 ± 18, 24 ± 9 and 20 ± 5 days at 20, 35 and 45C, respectively. Development of oxidized flavor followed a zero order reaction rate, activation energy was 15 kcal/mol.

Notes: COMPTES RENDUS