Firmness Measurement of Stored 'Delicious' Apples by Sensory Methods, Magness-Taylor, and Sonic Transmission
| Autor: | Judith A. Abbott, Louis A. Liljedahl, Henry A. Affeldt |
|---|---|
| Rok vydání: | 1992 |
| Předmět: | |
| Zdroj: | Journal of the American Society for Horticultural Science. 117:590-595 |
| ISSN: | 2327-9788 0003-1062 |
| DOI: | 10.21273/jashs.117.4.590 |
| Popis: | Additional index words. Malus domestica, ripeness, quality, postharvest Abstract. 'Delicious' apples (Malus domestica Borkh.) from five major U.S. production areas were tested after ≈3 months of commercial storage. Soluble solids concentration (SSC), titratable acidity (TA), Magness-Taylor (MT) firmness, and sonic transmission spectra were compared with ripeness (maturity in trade terminology) scores assigned by six U.S. Dept. of Agriculture (USDA)-licensed apple inspectors according to USDA Grades and Standards inspec- tion procedures. USDA ripeness categories are defined by textural and flavor terms. Inspectors in this test used visual, manual, oral, and auditory sensations to make their judgments, but firmness was the paramount characteristic judged. SSC and TA did not correlate with inspectors' scores, MT, or sonic measurements and thus are not satisfactory indices of ripeness for stored apples. Sonic resonance functions correlated significantly with mean inspectors' scores and with MT firmness. Inspectors' scores correlated slightly better with MT firmness than with sonic terms. MT is destructive and site-specific; in contrast, sonic measurements are nondestructive and representative of the entire fruit. Apple production in the United States in 1987 was nearly 4.9 million tons, valued at more than $906 million (U.S. Dept. Agr., 1989). Effective merchandising of such a volume of fruit requires effective sorting for several characteristics, particularly those in the Grade Standards (U.S. Dept. Agr., 1976). Domestic and foreign buyers both continuously demand better quality and a more uniform degree of ripeness. Renewed interest in apple ripeness (maturity in trade termi- nology) by the Agricultural Marketing Service (AMS) caused us to reevaluate simple tests that AMS inspectors could use and to examine the characteristics and methods that inspectors pres- ently use. It also afforded an opportunity to reexamine sonic vibrational characteristics for measuring texture in view of re- cent advances in electronic instruments and computers. SSC and TA content of apples are known to change with maturation and ripening. Texture often is equated with quality in apples, with firm, crisp apples being the ideal. Firmness is also frequently used as a measure of maturity and ripeness. In fact, the USDA-AMS Standards for maturity/ripeness cate- gories for fresh apples are Immature, Hard, Firm, Firm-ripe, Ripe, and Overripe (U.S. Dept. Agr., 1976). AMS inspectors rely mostly on firmness to make those assessments, particularly on apples that have been stored. Firmness is most commonly measured by a puncture test using a MT type fruit firmness tester (Abbott et al., 1976; Blanpied et al., 1978; Bourne, 1974; Magness and Taylor, 1925). Pro- vided that the probe geometry is comparable to that of the orig |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|