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- Author or Editor: Gerald G. Dull x
A near-infrared spectrophotometric method for estimating the soluble solids in honeydew melons is presented. The method is based on a body transmittance geometry in which the angle between the source incident beam and the detector is approximately 45°. The regression analysis of the spectral and chemical data utilizes a ratio of two second derivatives and resulted in a correlation coefficient of 0.85 and a standard error of calibration of 1.5. The numerator wavelength occurs in a carbohydrate absorption band, thus the method can be interpreted as a measurement of carbohydrates.
An instrument based on near infrared (NIR) reflectance techniques is described which is capable of determining nondestructively the percent soluble solids in whole honeydew, cantaloupe and watermelon samples. It utilizes a tilting interference filter technology for wavelength scanning and a silicon detector/amplifier for the detection of radiation which has penetrated through inner melon flesh. The standard error of prediction is of the order of 1.2 percent soluble solids for honeydew melons when compared with a standard refractometer analysis.
Whole dates (Phoenix dactylifera L.) were analyzed for moisture content using near infrared spectrophotometry in a direct transmittance geometry. In the calibration experiment using 72 samples, the correlation coefficient was 0.977 and the standard error of calibration (SEC) was 0.89%. When the calibration equation was used to predict the moisture in another set of 72 date samples, the standard error of performance (SEP) was 1.5%. When the method was used to sort these 72 dates into four industry-standard grades, 74% were correctly graded and 15% missed the grade by <1 SEC.
The terminology used to describe developmental stages of fruits is often confusing or even misleading. “Mature” and “ripe” are often used synonymously. We find reference to “green” fruit, based on skin or peel color, used interchangeably with “unripe”, the latter without referring to pigmentation but rather to a state of non-palatability. We see in the literature such words used synonymously as “overripe” and “senescent” in describing a fruit in a very late stage of development. Such terms as “early maturity”, “optimum maturity”, or “full maturity” leave some doubt as to what stage is actually under consideration. At best, different authors are not always referring to the same stage, even when dealing with the same fruit.
Heat penetration data showed that a 3 minute process at 104°C (220°F) with an FMC Steriotort reel speed of 5 rev/min was an adequate process for a high acid food product with an average pH of 3.9. Shear force, succulometer values, and Hunter “b” values were significantly related to maturity, but not to processing time.
Process time can be varied to produce a canned immature, medium-ripe, and ripe ‘Babygold 7’ peach [Prunus persica (L.) Batsch] with characteristics similiar to a commercial product. The most acceptable process for the immature, medium-ripe, and ripe fruit was 7, 9, and 5 minutes, respectively at 104°C with a reel speed of 5 rev/min in the Steriotort. Panelists preferred the ripe and medium-ripe fruit.
Acer rubrum L. ‘October Glory’ cuttings taken on 15 June 1984 were subjected to short day (SDT) (800-1700 HR) or short day plus night interruption treatments (NIT) (800-1700 plus 2200-200 HR) from 25 July until 22 Oct. 1984. Additional cuttings taken on 14 Aug. were subjected to the same photoperiod treatments from 10 Sept, until 22 Oct. For the 15 June cuttings, the NIT treatment induced significantly greater percent budbreak than the SDT, but did not induce significantly greater overwinter survival. Cuttings of 15 June that broke bud under NIT had significantly greater stem length and dry weight than cuttings that broke bud under SDT. SDT and NIT cuttings of 15 June that broke bud had significantly greater percent root carbohydrates, total grams of carbohydrates, and percent overwinter survival then cuttings that did not break bud. For the 14 Aug. cuttings, 1% of the cuttings broke bud, yet 95% (SDT) and 90% (NIT) of the cuttings survived the winter, and no difference in cutting carbohydrate levels, except stem starch, existed between the two treatments.