Date of Award:

1971

Document Type:

Dissertation

Degree Name:

Doctor of Philosophy (PhD)

Department:

Nutrition, Dietetics, and Food Sciences

Department name when degree awarded

Food Science and Technology

Advisor/Chair:

D. K. Salunkhe

Abstract

The effect of processing water quality, specifically calcium and magnesium salt content (0-500 mg/1) and the addition of chelating agents (0- 250 mg/ 1 of aminopolycarboxylic acids, polyphosphates, hydroxycarboxylic acids or phytates), upon physico-chemical and organoleptic characteristics of canned Jonathan and Delicious apple slices, Montmorency cherries and Blue Lake green beans was investigated.

Physical determinations: shear values, turbidity of syrup or brine measured via light transmittance, Hunter color and color difference meter readings and internal can corrosion; chemical composition: pectin as calcium pectate, volatile reducing substances, total acidity, pigment determinations, nitrate-nitrogen values; and sensory measurements: texture, shape, flavor, aroma, color value and uniformity of product and color value and turbidity of product brine or syrup were ascertained. Analyses of variance, Duncan's multiple mean comparison range tests and correlation or coefficients were calculated when appropriate.

Use of hard water (300 mg/1) as a processing medium for canned apple slices and sour cherries decreased color and flavor acceptability but increased firmness and shear values. Excessive hardness toughened cherry epidermis making texture undesirable. Addition of 250 mg/1 CaNa2EDTA to Delicious apple slices canned in water containing 300 mg/1 salts improved color and flavor while firmness was retained.

Delicious apple slices were firmer, and higher shear, nitrate-nitrogen and aroma scores and caused less detinning than Jonathan samples in all storage groups. As corrosion increased, nitrate-nitrogen, shear, firmness, flavor, aroma, and pigment values decreased. Color acceptability, reflectance, flavor and volatile reducing substance were higher and redness lower for Jonathan apple slices than Delicious samples stored at 35 and 75 F for 1 and 3 months, respectively, but not necessarily for samples stored at 100 F for 4 months. EDTA was ineffective in maintaining or improving Jonathan apple or Montmorency cherry quality, probably due ot the acidity of these cultivars.

Apple and cherry quality decreased as storage temperature and duration increased from 35, 75 to 100 F for 1, 3 and 4 or 5 months, respectively, for all samples except Delicious apple slices with CaNa2EDTA. EDTA did provide most color protection in sour cherries, and citric acid, best flavor and aroma scores, while commercial and tap water processed sour cherries showed most deterioration, but none were of acceptable commercial quality after 5 month storage at 100 F. When comparing 1 month storage at 35 F with 3 months at 75 F, analyses of variance showed significant differences for every cherry characteristic measured except texture judged subjectively. All F values for apple storage variables were significant.

Blue Lake green beans canned using distilled water or with 250 mg/ 1 CaNa2EDTA had higher color and greenness values, less turbidity, generally better flavor and aroma, but lower shear, shape and firmness scores than tap or hard water or commercially processed green beans. Addition of 250 mg/1 ascorbic acid to hard water used to process green beans retained greenness, clarity of brine, flavor and aroma while reducing slough and splitting of pods, when stored 4 months at 75 F.

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