Processing and enzymatic treatment effects on Louisiana-grown fresh satsuma juice

Authors: Beaulieu, John; Tully, Maureen; Stein, Rebecca; OBANDO-ULLOA, JAVIER - Universidad De Chile

Submitted to: Journal of the American Society for Horticultural Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/3/2014
Publication Date: 7/7/2014
Publication URL: https://handle.nal.usda.gov/10113/59763
Citation: Beaulieu, J.C., Tully, M.A., Stein, R.E., Obando-Ulloa, J.M. 2014. Processing and enzymatic treatment effects on Louisiana-grown fresh satsuma juice. Journal of the American Society for Horticultural Science. 139(4):374-387.

Interpretive Summary: In recent post-hurricane years (Katrina and Isaac), the Louisiana citrus industry has suffered immensely due to flooding, wind, and salt water intrusions, which led to a significant reduction in citrus production/interest in Louisiana. To restore growth, stability, and prosperity to the Louisiana farmer, there is need to research methodologies to better understand the unique produce of Louisiana, as well as develop value added systems for processing and marketing. Without augmented methods to process crops like satsuma, both demand and incentive to produce and grow local commodities has diminished annually. Juicing locally produced satsuma could become a viable alternative to diminish crop losses and boost a struggling industry. Initial pilot plant trials were performed at the Agricultural Research Center, using only a fruit press, enzymatic treatments and an ultrafiltration (UF) unit. The objective was to assess the viability of rapidly producing high quality fresh, not-from-concentrate (NFC) satsuma juice from locally grown fruit without traditional commercial machinery. Forty-four flavor volatile compounds were recovered in freshly pressed LA-grown satsuma juices throughout a single growing season, and 31 were positively identified. Limonene was the dominant integrated peak in almost all peeled pressed fruit juices, even when samples were diluted 10-fold. Peel removal resulted in 98.4% of the total volatiles to be lost, and the distribution of the volatiles remaining was markedly different compared to whole pressed juice. Even careful hand extraction of the peels introduced minor amounts of peel oil compounds into the juices, as evidenced by limonene and other terpenes in control juices. Certain compounds (carvone, (E)-geraniol and ß-caryophellene) were not present in control and enzyme treated peeled pressed juices. 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. Analysis of concentrates made from peeled pressed juice and reconstituted satsuma juices indicated clearly that most desirable aroma/flavor volatile compounds are stripped from juices during concentrating. In general, peeled pressed fruit produced an acceptable, mildly citrus flavored, balanced acidity, sweet not-from-concentrate fresh juice. Yet, without additional equipment inputs (peeler), or adding essence or flavor packs back into the commercial product, it will be difficult to rapidly and cheaply produce a fresh seasonal satsuma juice that is safe and consistently accepted by the consumer.

Technical Abstract: A study was performed to evaluate the ability to rapidly produce fresh satsuma juice from local fruit with minimum processing inputs. Volatile flavor and aroma compounds, subjective assessments, and quality parameters were used to determine the qualitative changes that occur from different juice processing techniques, storage conditions, and enzymatic treatments. Forty-four compounds were recovered in freshly pressed LA-grown satsuma juices throughout a single growing season, and 31 were positively identified. Based upon recovery and a consensus approach dictated by mandarin and satsuma literature, 19 compounds were evaluated. Limonene was the dominant integrated peak in almost all peeled pressed fruit juices, even when samples were diluted 10-fold. Peel removal resulted in 98.4% of the total volatiles to be lost, and the distribution of the volatiles remaining was markedly different compared to whole pressed juice. Even careful hand extraction of the peels introduced minor amounts of peel oil compounds into the juices, as evidenced by limonene and other terpenes in control juices. Carvone, (E)-geraniol and ß-caryophellene were not present in control and enzyme treated PPJ throughout the study. 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. Analysis of rotavap concentrates made from peeled pressed juice and reconstituted satsuma juices indicated clearly that most desirable aroma/flavor volatile compounds (based upon consensus in the literature) are stripped from juices during concentrating. In general, peeled pressed fruit produced an acceptable, mildly citrus flavored, balanced acidity, sweet NFC fresh juice. Yet, without additional equipment inputs (peeler), or adding essence or flavor packs back into the commercial product, it will be difficult to rapidly and cheaply produce a fresh seasonal satsuma juice that is safe and consistently accepted by the consumer. Data reported suggest more attention would be required to maintain the top-notes and subtle volatile balance via use of industrial equipment, or by adding back essence or flavor packs prior to bottling/pasteurization.