Flavour is an important quality trait of food and beverages. As the demand for natural aromas increases and the cost of raw materials go up, so does the potential for economically motivated adulteration. In this study, gas chromatography-combustion-isotope ratio mass spectrometry (GC-C-IRMS) analysis of volatile fruit compounds, sampled using headspace-solid phase microextraction (HS-SPME), is used as a tool to differentiate between synthetic and naturally produced volatile aroma compounds (VOCs). The result is an extensive stable isotope database (IsoVoc—Isotope Volatile organic compounds) consisting of 39 authentic flavour compounds with well-defined origin: apple (148), strawberry (33), raspberry (12), pear (9), blueberry (7), and sour cherry (4) samples. Synthetically derived VOCs (48) were also characterised. Comparing isotope ratios of volatile compounds between distillates and fresh apples and strawberries proved the suitability of using fresh samples to create a database covering the natural variability in δ¹³C values and range of VOCs. In total, 25 aroma compounds were identified and used to test 33 flavoured commercial products to evaluate the usefulness of the IsoVoc database for fruit flavour authenticity studies. The results revealed the possible falsification for several fruit aroma compounds.

Apple thinning of cv. 'Golden Delicious' and cv. 'Idared' was studied after the application of 6-benzyladenine (BA) 100 mgl-1 and 50 mgl-1 respectively, applied at different time of blooming period and over a wider range of fruitlet diameter. When BA 100 mgl-1 was applied on cv. 'Golden Delicious', significant reduction in final fruit number per tree was observed if applied at the end of blooming period or when fruitlet diameters were 6 mm, 15 mm or 20 mm, but thinning was not significant if applied at full bloom or at 10 mm or 25 mm fruitlet diameter. The share of bigger fruits of cv. 'Golden Delicious' (> 65mm) was increased at all BA application time treatments, but significantly only in the treatment of hand thinned trees. Regarding the BA applications carried out on cv. 'Idared', significant thinning response was noticed in the case of BA sprayed at the end of bloom and at 10 mm of fruit diameter. The mean fruit weight of cv. 'Idared' apples was increased significantly only if BA was applied at 10 mm fruitlet diameter. Although the thinning results were inconsistent for two studied cultivars it was demonstrated from the trial that BA could be active as a thinner if applied over a wider phenological interval, at the end of blooming period up to 20 mm fruitlet diameter.

Summary To find the most appropriate rates of application of plant growth regulator (PGR) thinning-agents for a common slender spindle apple (Malus × domestica Borkh.) orchard, different volumes of dilute 1-naphthaleneacetic acid (NAA) and 6-benzyladenine (BA) were sprayed ha⁻¹. Mature ‘Jonagold’/M.9 trees, 3.0 – 3.5 m high and 1.2 – 1.5 m wide, planted in a single row system with 3,030 trees ha⁻¹, were used. Significant thinning was observed in the case of dilute sprays of NAA at 10 mg l⁻¹, or BA at 100 mg l⁻¹, to run-off, using 2,000 l ha⁻¹ or 1,500 l ha⁻¹; while 1,000 l ha⁻¹ did not result in sufficient thinning. Thinning using smaller volumes (250, 500, or 750 l ha⁻¹) was also significant if the concentration of PGR thinner was proportionally higher (i.e., based on the 1,500 l ha⁻¹ application rate of more dilute sprays of NAA at 10 mg l⁻¹ or BA at 100 mg l⁻¹). Spray distribution measurements in the crowns showed better spray deposits when higher water volumes (i.e., more dilute PGR solutions) were sprayed at all positions (bottom, middle, or top) of the canopy. At 2,000 l ha⁻¹, 54 – 72% coverage of the leaf area was observed; but, at 250 l ha⁻¹, coverage was only 10 – 21%. The lower 30% of the canopy was covered poorly when smaller volumes of water (250, 500, or 1,000 l ha⁻¹) were applied. When 1,500 l ha⁻¹ was sprayed, good coverage of the lower and upper surfaces of the leaves occurred, and no differences in canopy positions were measured. It was concluded that 1,500 l ha⁻¹ (i.e., dilute PGR) spraying was the most appropriate volume to use when calculating the dose of NAA or BA to be applied ha⁻¹ to common (3.0 – 3.5 m-high) mature slender spindle apple orchards on M.9 rootstock. This study was part of the ISAFRUIT Smartfruit Project, aimed at improving existing methods for apple crop regulation with more precise use of PGR thinning agents and with minimum impact on the environment.

Summary Mature slender spindle ‘Jonagold’/M.9 apple (Malus × domestica Borkh.) trees were thinned using 10 mg l^–1 1-naphthaleneacetic acid (NAA) or 100 mg l⁻¹ 6-benzyladenine (BA) and an axial fan sprayer at a spray volume of 1,500 l ha⁻¹ applied to the whole canopy, or with smaller volumes, where only the upper half of each canopy was sprayed. Partial spray applications of NAA or BA (at 1,000 l ha⁻¹, 750 l ha⁻¹, or 500 l ha⁻¹) to the upper half of the trees did not cause any reduction in final fruit numbers on the upper half, or on the lower half of each tree. When the whole tree was sprayed to run-off with the same thinning agent, or at 1,500 l ha⁻¹, successful thinning on both the upper and lower parts of the canopy occurred. Good spray coverage (from 51% to 77%) was also observed on leaves at all canopy positions measured, when whole trees were sprayed at 1,500 l ha⁻¹.The development of an innovative crop load regulation strategy was an objective of the ISAFRUIT Smartfruit Project.