There are very few studies detailing the aroma, astringency, and flavor of rabbiteye blueberry [RAB (Vaccinium ashei)] fruit typically grown in the southeastern United States. The objectives were to investigate the rapid and qualitative solid-phase microextraction gas chromatographic–mass spectrometry volatile composition of several local RAB cultivars with an overall goal to build a database of possible flavor and aroma compounds. Volatile profiles were obtained in five Louisiana-grown RAB cultivars (Brightwell, Climax, Premier, Powder Blue, and Tifblue) assayed at four maturities. The method routinely captured 53 volatiles, including 12 aldehydes, six alcohols, 11 esters, four ketones, 17 terpenoids, one furan, and two aromatics. Of the 33 compounds considered important in blueberries, 17 were recovered in the RAB cultivars assessed. Herein, 10 compounds were recovered for the first time in blueberry (Vaccinium sp.) and five of those compounds were confirmed with standards [2-ethylfuran, (E)-2-pentenal, (Z)-dehydroxylinalool oxide, (E)-dehydroxylinalool oxide and 1,4-cineole]. In general, terpenoids and their subclass linalools were the most significant volatiles followed closely by esters, aldehydes, and then alcohols. Terpenoids and linalools displayed the greatest significant differences in ‘Powder Blue’ and ‘Premier’. Esters and aldehydes were the most significant compound classes based on cultivar effect per maturity in firm-ripe fruit. From the suite of 17 of the 33 important compounds in upright blueberry, 10 were recovered across the five cultivars at four maturities that displayed a high level of significance. These were linalool, methyl 3-methylbutanoate, 1,8-cineole, (E)-2-hexanal, (Z)-3-hexenal, (Z)-3-hexenyl acetate, limonene, hexyl acetate, hexanal, and α-terpineol. These data will be useful to evaluate aroma volatiles in RAB and changes in processed and value-added byproducts.
John C. Beaulieu, Rebecca E. Stein-Chisholm and Deborah L. Boykin
John C. Beaulieu, Maureen A. Tully, Rebecca E. Stein-Chisholm and Javier M. Obando-Ulloa
A study was performed to evaluate the ability to rapidly produce fresh satsuma (Citrus reticulata) juice from local fruit with minimum processing inputs. Volatile flavor and aroma compounds, subjective assessments, and quality parameters were used to determine the changes that occur from different juice processing techniques, storage conditions, and enzymatic treatments. In freshly pressed Louisiana-grown satsuma juices, 44 compounds were recovered, of which 31 were positively identified. Based on volatile recovery and a consensus approach used in orange-fleshed Citrus species reported in the literature, 19 compounds were evaluated. Limonene was the dominant integrated peak in all unpeeled and peeled pressed juices (PPJ). Peel removal resulted in 98.4% of the total volatiles being lost and the distribution of the volatiles remaining was markedly different compared with whole-pressed fruit juice. Aside from a 63.4% increase in valencene after enzyme treatments, there seemed to be no marked volatile, subjective, or quality improvements from the enzymes used in this study. In general, peeled pressed fruit produced an acceptable, mildly citrus-flavored, balanced acidity, sweet, not-from-concentrate juice. Concentrates made from PPJ and reconstituted satsuma juices indicated clearly that most desirable aroma/flavor volatile compounds were stripped from juices during concentrating. Data reported suggest more attention would be required to maintain the top notes and subtle volatile balance during commercialization in rapidly produced fresh satsuma juices through use of industrial equipment (peeler) or by adding back essence or flavor packs for consistent consumer satisfaction.
Rebecca E. Stein-Chisholm, John W. Finley, Jack N. Losso and John C. Beaulieu
Juice production is a multibillion dollar industry and an economical way to use fruit past seasonal harvests. To evaluate how production steps influence not-from-concentrate (NFC) blueberry (Vaccinium sp.) juice recovery, bench top and pilot scale experiments were performed. In bench-top, southern highbush (SHB) blueberry (Vaccinium darrowii × Vaccinium corymbosum) and rabbiteye blueberry (RAB) (Vaccinium ashei) were pressed at varying temperatures. Press treatments included ambient temperature, frozen then thawed, and frozen then heated berries. In addition, two commercial pectinase enzymes were evaluated. Three batches were pressed and average juice recovery was calculated. The highest average free juice recovery (68.8% ± 1.1%) was attained by heating frozen berries and treating with enzyme. Comparing berry species pressed, SHB blueberries produced significantly more juice than RABs. There were no significant differences between enzymes used between berry species. Using this preliminary data, the optimum juice recovery method was then transferred to pilot scale processing. RABs were heated and treated with enzyme then pressed. Free juice recovery from the pilot scale was 74.0% ± 1.0%. Total juice recovery was calculated to be 87% ± 0.6%. With this information, further refinement of juice processes could increase juice production output for small-scale producers and expand local outlets for growers to market their crops as well as create new opportunities for growth in the fresh juice market segment.