Pulpwash

There is also a method in the AOAC manual for the analysis of benzoic acid in orange juice (994.11). However, this method was not designed to detect benzoic acid as a preservative. In Florida, when pulpwash was prepared benzoic acid used to be added as a marker, so that if the pulpwash was added to a juice it would be detected. However, it is believed that this practice has now been stopped. 

Orange pulpwash (water extraction of soluble fruit solids from orange pulp) can contribute significantly to the bitterness... 

Royo Iranzo and Aranda (1 ) and Royo Iranzo et aK (2) found from one half to one third of the commercial European bottled orange juices tested were adulterated. Mears and Shenton [3) reported the most common form of adulteration in the early 1970 s was the use of fruit by-products such as extracts of peel and pulp (pulp-wash). It appears that the problem has continued into the 1980 s. Three orange juice surveys in the United States (162 samples obtained from retail outlets) conducted by the Florida Department of Citrus during 1979 and 1980 indicated gross adulteration by orange pulpwash (PW) and/or sugars and/or dilution (Petrus et al., unpublished data). 

Visible and Ultraviolet Absorption and Fluorescence Excitation and Emission Characteristics of Florida Orange Juice and Orange Pulpwash... 

Of the remaining 29 FCOJ samples, 86 percent indicated pulpwash adulteration in amounts up to 60 percent. Twenty-five percent (6 of 25) of the SSOJ samples indicated pulpwash adulteration in amounts to 40 percent. State of Florida Citrus Fruit Laws (3J govern the inspection, grading, certification, sale and shipment within or without the State of all citrus fruit and the products thereof whether canned or concentrated. The laws also govern the licensing or certification of citrus fruit inspectors by the United States Department of Agriculture. There are no required inspections, grading or certification of a product repacked by other distributors out of the state of Florida. 

Lifshitz et aK ( ) investigated the purity of Israeli citrus juice by a multivariate method. They selected 5 analytical parameters and concluded that adulteration or dilution of 15% or more was very likely to be detected at a 1% level of significance. However, adulteration with orange pulpwash was not included in their study. 

The purpose of this presentation is to discuss the visible and ultraviolet absorption and room temperature fluorescence characteristics of alcoholic solutions of Florida produced orange juice and pulpwash samples, and to relate the characteristics to qualitative detection and quantitative approximation of adulteration of frozen concentrated and single-strength orance juices. Experimental details of our procedures may be found elsewhere (15). 

Figure 3. Spectral (VIS/VV) absorption curve comparison of commercial Florida-produced frozen concentrated orange juice (--------) and orange pulpwash ( — )...

Excitation (nm) Emission (nm) Range Setting Excitation Spectra Orange Juice Pulpwash ... 

Fig. 7 and 8 show the absorbance sum and ratio distribution of Florida commercial packed frozen orange pulpwash concentrate (reconstituted or calculated to 12.8° Brix). Sampling period was from 1971 through 1979. Absorbance sum of 206 samples showed a minimum of 2.617, maximum of 4.992, mean and standard deviation of 3.781 0.473, and coefficient of variation of 12.5%. Absorbance ratio showed a minimum of 0.017, maximum of 0.112, mean and standard deviation of 0.048 0.020, and coefficient of variation of 41.7%. 

Inspection of the distribution plots and data revealed more variation in pulpwash than FCOJ, indicating standardization of Florida FCOJ products. However, there are many processing variables in orange pulp washing, such as number of, and mechanical... 

Figure 7. Distribution of absorbance sum of Florida-produced orange pulpwash (N = 206 mean = 3.781 standard deviation = 0.473)...

Case 1. If the results indicate a combination of orange juice, pulpwash and dilution, then equation 8, 9 and 10 are reported as calculated and product formulation equals 100 percent. 

The equations were performed on the data obtained from the 416 FC0J samples previously discussed. Qualitatively the absorption and fluorescence spectra did not indicate the presence of orange pulpwash. Therefore, the juices were examples of Case 3, and orange juice content reported as % TCM (equation 7). Statistical analysis of the results showed a mean of 99.6% TCM and standard deviation of 8.5. 

To further verify the equations, 29 unknown samples (4 sets) composed of various combinations of orange juices, and/or pulp-washes and/or product dilutions were prepared by others for analysis. Calculated values were correlated with actual values and gave the following coefficients of determination orange juice content r2 = 0.942 pulpwash content r2 = 0.981 and dilution r2 = 0.937. Even with significant coefficients of determination, it must be stressed that the equations provide only approximations of sample formulations. The constants used in the equations were based on results obtained from commercial Florida... 

Visible and ultraviolet absorption and fluorescence spectra, obtained from alcoholic solutions of a commercially packed (out of the State of Florida) FCOJ, are presented in Fig. 9, 10, 11 and 12. Qualitatively, Fig. 9 reveals a lack of resolution in the visible absorption region and a well resolved peak at 280 nm. Comparison with Fig. 1 and 3 shows its absorption characteristics to be more similar to those of orange pulpwash in Fig. 3, indicating adulteration by pulpwash addition. Fluorescence excitation spectra (Fig. 10, 11) reveal well defined peaks at 270-75 nm, and Fig. 12 a shoulder at 270-75 nm. The spectra appear deformed when compared to Fig. 2 and 4 of pure orange juice. However, characteristics are similar to those obtained from pulpwash and very similar to those obtained from prepared model systems. Qualitatively both visible and ultraviolet absorption, and room temperature fluorescence indicate the presence of pulpwash in the FCOJ sample. The spectra are complementary. Absorption also did not indicate further adulteration by dilution which would have been denoted by weaker overall absorption and a shift at 227 nm to shorter wavelength. The sum of absorption at 443, 325 and 280 nm is 0.098 + 1.040 + 1.622 = 2.760 absorbance units. Florida State statute 20-64.07(l)(a) requires FCOJ to be 44.8° Brix which reconstituted to 12.8° Brix (16) and Federal standards, Section 52.2582(a), require 41.8° Brix, reconstituted to not less than 11.8° Brix (17). Therefore, the sum of absorbance is multiplied by the ratio of 12.8 to 11.8° Brix, with a corrected sum of 2.995. The sample absorbance ratio at 443/325 nm is 0.098/1.040 which is equal to 0.094. If the sum and natural log ratio values are substituted into the regression equation ... 

In conclusion, it has been shown that the visible and ultraviolet absorption, and room temperature fluorescence spectra, obtained from alcoholic solutions of orange juice and related products, may be used for product characterization. The complementary absorption and fluorescence spectra may be utilized for the qualitative detection of adulteration of reconstituted frozen concentrated and single-strength orange juice with pulpwash. Previous investigations (chemical and elemental profile analyses)... 

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