EXPLORATORY EXPERIMENTS TO IDENTIFY CHEMICAL REACTIONS CAUSING FLAVOR DETERIORATION DURING STORAGE OF CANNED ORANGE JUICE. I. INCOMPATIBILITY OF PEEL‐OIL CONSTITUENTS WITII THE ACID JUICE^a

Abstract

It is quite apparent that the flavor deterioration which takes place during the unrefrigerated storage of canned orange juice is greater than that which is encountered during the similar storage of canned non-citrous fruit products. Observations made in this laboratory with canned Florida Valencia orange juice stored a t any temperature above 7O0F.(21"C.) may be described by saying that the predominant off-flavor which develops under such conditions is ' terebinthine " in character. The terebinthine factor is acrid and camphoraceous, and is often most clearly apparent as an after-flavor, perceived after swallowing the juice. Similar juice stored at temperatures which never exceed 70°F.(21"C.) also depart in time from a desirable fresh flavor, but in this case the off-flavor has a complex and variable quality which may be named "stale" for purposes of discussion, and which is conspicuous in such samples because a t the lower temperature the terebinthine factor does not become dominant. Such empirical observations indicate quite clearly that the over-all degradation in flavor during storage involves a large number of different chemical reactions, differing in regard to the temperature coefficient of reaction rate.It has been postulated in the past that flavor degradation is due to microbiological activity (30) o r to changes in nitrogen compounds (19), or to products resulting from a postulated initial oxidation of juice components. The primary oxidation products are not themselves off-flavored but are thought to constitute an unstable system which leads to the ultimate production, from the fatty components of the juice, of substances which impart to the flavor a rancid quality (20). It is probably fair to say that the proponents of these hypotheses were seeking explanations of the stale, rather than the terebinthine, flavor factors.

Degradation Products Formed in Canned Single‐strength Orange Juice During Storage

“…This compound, reported in tomatoes by Buttery et al (197 1) could be the unidentified phenol isolated ' by Blair et al (1950) from orange juice. When added to control juice, most taste panelists remarked that this compound imparted an "old fruit" or "rotten" flavor to juice.…”

Study of chemical changes in pasteurised orange juice during shelf-life: A fingerprinting-kinetics evaluation of the volatile fraction

“…Increase in terpene hydrocarbons such as α-terpinolene and α-terpinene can be linked to the oxidative reaction and/or acid-catalysed hydration-dehydration reactions of terpenes as suggested by Perez-Cacho and Rouseff (2008a); Blair, Godar, Masters, and Riester (1952). Some researchers observed a twofold increase of p-cymene in citrus oil at 5°C during 12 months of storage which could be attributed to rearrangement, hydrogenation and dehydrogenation of α-terpinene, γ-terpinene and limonene (Njoroge, Ukeda, & Sawamura, 1996).…”

“…In our work, esters such as octyl acetate and α-terpinyl acetate showed important changes. Hydrolysis of esters producing acids during storage of orange juice could be the possible reason (Blair et al, 1952).…”

Orange juice quality with an emphasis on flavor components

“…116 d-Limonene, the principal constituent of orange peel oil, was thought to undergo a series of hydration-dehydration reactions forming er-terpineol, 1,4-cineole, and other products. 35 Another off-flavor, similar to that of stored heat-processed orange juice, develops from the gamma irradiation of the juice. The flavor of these juices has been described as sweet, tart, oxidized, cooked, and cabbage-like by various investigators.…”

“…Most of the volatile constituents which contribute to the distinctive aroma of orange juice have their origin in the peel oil. 35 However, orange juice volatiles differ from peel oil by having a greater number of saturated and unsaturated alcohols, aldehydes and esters. 369 The major esters of the juice volatiles are 3-hydroxy hexanoate, ethyl acetate, and ethyl butyrate.…”