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ARS Home » Southeast Area » New Orleans, Louisiana » Southern Regional Research Center » Food Processing and Sensory Quality Research » Research » Publications at this Location » Publication #311021
Title: Physicochemical properties and aroma volatile profiles in a diverse collection of California-grown pomegranate (Punica granatum L.) germplasm

Author
item Beaulieu, John
item Lloyd, Steven
item Preece, John
item Moersfelder, Jeff
item STEIN-CHISHOLM, REBECCA - Former ARS Employee
item OBANDO-ULLOA, JAVIER - University Of Chile

Submitted to: Food Chemistry
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/5/2015
Publication Date: 2/17/2015
Citation: Beaulieu, J.C., Lloyd, S.W., Preece, J.E., Moersfelder, J.W., Stein-Chisholm, R., Obando-Ulloa, J.M. 2015. Physicochemical properties and aroma volatile profiles in a diverse collection of California-grown pomegranate (Punica granatum L.) germplasm. Food Chemistry. 181:354-364.

Interpretive Summary: Pomegranate (Punica granatum L.) is one of the oldest cultivated fruits, as well as richest in history and folklore. Worldwide, there are thousands of accessions and more than 500 pomegranate varieties known with around 50 commercially recognized cultivars. The germplasm has a high genetic diversity of morphological, quality and sensory traits. Consumption of phytonutrient-rich fruits, juices, and functional foods have increased markedly in recent years; however, colorful fruits that provide well documented health benefits may convey astringency and sourness that some consumers do not appreciate. With the aid of the USDA, ARS, National Clonal Germplasm Repository, we assessed wide organoleptic properties in a small collection of California-grown pomegranate cultivars. The goal was to evaluate overall variations in quality traits (sugar, acidity, sweetness, color, flavor etc.) which varied between “high” and “low” in juiced pomegranate cultivars from around the world that were grown in California. Optimum quality fresh pomegranate fruit were mechanically pressed. Juices were analyzed for quality attributes (Brix, color, pH and TA), anthocyanidins, organic acids, and aroma volatile compounds. Data were subjected to ANOVA, Dunnett’s test and principal components analysis (PCA). Results allowed specific cultivars to be distinguished based on Brix (soluble solids content), pH, titratable acidity (TA), the Brix:TA acid ratio (maturity index), and upon the abundance of certain volatiles. The cluster analysis demonstrated which cultivars are more similar or dissimilar compared with the U.S. standard cultivar, Wonderful. Information contained herein may help the pomegranate juice industry to better select raw juice materials in order to ultimately satisfy consumers.

Technical Abstract: There are thousands of pomegranate accessions and more than 500 known pomegranate cultivars with around 50 available commercially, exhibiting different growing characteristics and quality attributes; such as fruit size, color, shape, seed hardness, taste and flavor traits which are sometimes not well correlated with morphological or genetic traits. Consumption of phytonutrient-rich fruits, juices, and functional foods have increased markedly in recent years; however, colorful fruits that provide well documented health benefits may convey astringency and sourness that some consumers do not appreciate; therefore, with the aid of the USDA, ARS National Clonal Germplasm Repository, Davis, CA, we assessed wide organoleptic properties in a small collection of California-grown pomegranate cultivars. The goal was to evaluate overall differences in quality traits (sugar, acidity, sweetness, color, flavor etc.), which varied between “high” and “low” in juiced pomegranate cultivars from around the world that were grown in California. Optimum quality fresh pomegranate fruit were hydraulically pressed. Juices were analyzed for quality attributes (Brix, color, pH and TA), anthocyanidins, organic acids, and aroma volatile compounds. Data were subjected to ANOVA, Dunnett’s test and principal components analysis (PCA). The results allowed Nusai to be distinguished with the highest Brix, while Nikitski Ranni, Kara Gul, and Haku-botan showed higher TA than the Wonderful control (DPun 81). On the other hand, Fleischman, Salavatski, Sin Pepe, Nusai, and Ovadan showed a higher pH than Wonderful (DPun 81), while in other cultivars (Haku-botan and Kara Gul) the pH was lower. Fleischman, Nusai, and Sin Pepe had significantly higher Brix:acid ratios (maturity index) than Wonderful (DPun 81). Haku-botan, Sin Pepe, Fleischman, and Myagkofemyannyi Rozovyi had significantly higher L* juice color (lighter) than all other cultivars. The lowest total anthocyanidin content was identified in the juice of Haku-botan, Fleischman, Sin Pepe, Myagkofemyannyi Rozovyi, and Nusai. Fleischman, Salavatski, Sin Pepe, Myagkofemyannyi Rozovyi, and Nusai, showed the lowest total organic acid content, while the juice of Kara Gul and Fleischman showed the highest and lowest total organic acid content, respectively. (Z)- & (E)-3-hexenol and 1-hexanol were the dominant aroma compounds in the pomegranate cultivars grown in California. (Z)- & (E)-3-hexenol allowed the separation of Kara Gul, Haku-botan, Wonderful (DPun 81), and commercial Wonderful based on PCA. Terpene content allowed the separation of Myagkosemyannyi Rozovyi, while Nikitski Ranni and Salavatski were distinguished from the other cultivars by the relative content of (E)-2-hexenal and (Z)-3-hexenal. In summary, this is the first report where juice quality and aroma volatile profiles of different pomegranate cultivars from around the world, grown in California, were compared against the U.S. standard Wonderful. This would help the pomegranate juice industry to better select raw juice materials in order to ultimately satisfy consumers.