Texture Changes During the Dark‐ripe Processing of Olives

Abstract

I n addition to its role in the production of new flavors, pickling in brine often is associated with pronounced alterations in the texture of the brined product. Characteristically, softening has been observed frequently, and the relationship of such softening to the breakdown of pectic materials of the cell walls has been well documented (4, 6, 21, 25).On the other hand, some evidence has accumulated which suggests that during the normal brining process a firming effect may predominate. The crisp texture of sauerkraut, of cucumber pickles, and of Spanish-style olives is well-known. In brined cherries, McCready and McComb (9) note a definite "firming reaction" during the brining process. Moreover, olives made by the "dark-ripe" method seem to be less susceptible to softening during heat treatment than fresh, un-brined ones.Besides the brining operation, the dark-ripe processing of olives ( 2 ) involves treatment with lye solutions (with attendant aeration for color production), leaching of the lye from the olives, salting in 2.5% NaCl filling solution, and retorting at 240"-250°F. These treatments undoubtedly affect the final texture of the canned olive. The present investigation has been undertaken to ascertain the respective contributions of each processing phase to the textural quality of the finished product. MATERIALS AND METHODSThe raw materials of the experiments were Ascolano and Sevillano olives, harvested a t various maturity stages during 1951, 1959, and 1953. Inasmuch as the experimental treatments varied from year to year, these are best considered in chronological order.The 1951 experiments. Ascolano olives of a single maturity were harveeted from one tree a t Davis (Yo10 Co.), California, for the initial experimentation. The olives were put in eolutions in covered, 2-quart, canning-type glass jars. Some jars of fruit were permitted to ferment normally in 40" salometer (10%) brine with an added "starter" inoculum of Lactobacillus plantarum. I n addition, sterile solutions were prepared with 5% formalin in distilled water to evaluate the effects of certain chemicals. These chemicals were as follows: sodium chloride (0, 0.01, 0.1, 1.0, and 10.0%) ; lactic acid (0, 0.01, 0.1, 1.0, and 10.O%), and calcium chloride (with calcium ion concentrations of 0, 10, 100, 1,000, and 10,000 p.p.m.). Sodium fluoride (0.4%0) and sodium benzoate (0.2oJ0) had to be added later to some of these solutions in order to inhibit microbial activity.For texture evaluation, olives were pitted with a laboratory cork-borer, cut in half longitudinally, and placed in the test-box of a Tenderometer.' Texture measurementa were made on raw and cooked (Le., 280 g. pitted olives boiled 5 minutes i n 500 ml. distilled water) olives initially and at weekly intervals during the 3-month period of holding. At the end of 3 months, the texture of olives held in the sterile solutions with various chemicals was also measured. Histological specimens in parafin were prepared for each type of treatment according to standard microtechnical methods ...

INFLUENCE OF SALTS AND pH ON THE FIRMNESS OF OLIVES IN ACID CONDITIONS

“…The presence of NaCl did not have any effect on the texture of either type of green olives. Lactic acid increased the softening rate of green olives by a higher proportion than acetic acid.been reported for olives (Sterling 1956) and pickles (Fleming et al 1987) when monovalent cations are present, although this effect may be attributed to the 'To whom all correspondence should be sent.…”

“…Texture of olives is an important quality attribute and there is little information about texture changes in olives during processing in acid conditions (Sterling 1956;Garrido et al 1986). The two types of table olives in the USA and Spain are ripe olives and Spanish style green olives.…”

“…been reported for olives (Sterling 1956) and pickles (Fleming et al 1987) when monovalent cations are present, although this effect may be attributed to the 'To whom all correspondence should be sent.…”

Colour and texture changes during sterilization of packed ripe olives

“…The texture of ripe olives can be influenced by many factors (Sterling, 1956;Chung et ul., 1972), one of the most important being calcium ions (Garrido, 1980;Garcia et ul., 1993). Calcium is currently added to most commercial processed fruits and vegetables to prevent texture loss (McFeeters & Fleming, 1991;Fleming et al, 1993), although no data are available on the effect of calcium on the kinetics of texture changes (McFeeters & Fleming, 1990).…”

CHANGES IN PECTIC SUBSTANCES OF FOUR VARIETIES OF PICKLING CUCUMBERS DURING FERMENTATION AND SOFTENINGa

“…Whereas the other extractions were fairly uniform and represented trends, erratic results were obtained with this fraction. Calcium can combine with certain types of pectic substances, and by forming a calcium pectate gel, contribute to firmness (12,18,11). For this reason calcium analyses were made on the dried tissues of fresh cucumbers with and without the extraction of sugars by 95% ethanol, and on dried tissues of the "firm" salt stock, unfreshened and partially freshened.…”