Source: UNIVERSITY OF VERMONT submitted to
THE FATE OF HEAVY METALS AND OTHER CONTAMINANTS OF MAPLE SAP AND SYRUP
Sponsoring Institution
National Institute of Food and Agriculture
Project Status
TERMINATED
Funding Source
Reporting Frequency
Annual
Accession No.
0195867
Grant No.
2003-34157-13001
Project No.
VT-BO-041SG
Proposal No.
2004-06117
Multistate No.
(N/A)
Program Code
BA
Project Start Date
Jul 1, 2003
Project End Date
Jun 30, 2005
Grant Year
2004
Project Director
Perkins, T. D.
Recipient Organization
UNIVERSITY OF VERMONT
(N/A)
BURLINGTON,VT 05405
Performing Department
PLANT BIOLOGY
Non Technical Summary
Maple syrup is typically a very pure product, however occasionally various contaminants may be present. This project will examine the points at which contaminants may be introduced, and ways to effectively reduce contaminants by alterations in equipment or management of sugaring operations
Animal Health Component
(N/A)
Research Effort Categories
Basic
50%
Applied
50%
Developmental
(N/A)
Classification

Knowledge Area (KA)Subject of Investigation (SOI)Field of Science (FOS)Percent
7110620115020%
7110680101010%
7110680115010%
7112099115020%
7120620115020%
7122099115020%
Goals / Objectives
The goals of this research are to examine sources of, and sinks for, contaminating substances of maple sap and syrup, to explore methods to reduce levels of these substances in the finished product, and to develop methods of detection of contaminants. Because of the tremendous variability in equipment used in the collection and processing of maple sap into syrup by individual producers, it is necessary to identify and eliminate or modify processing equipment and methods which introduce undesireable substances in sugaring operations.
Project Methods
The effects of equipment cleaning practices will also be examined. Efficiency of current filtering processes to remove particulate contaminants also be studied. The naturally-occurring level of paraformalehyde in maple sap and syrup will be explored by determining PF levels in sap and syrup free of added PF, and by measuring formation of PF in sap and sucrose solutions. The efficacy and analytical methods to detect illegal substances to bleach (lighten) syrup will be investigated.

Progress 07/01/03 to 06/30/05

Outputs
Maple syrup is a pure and natural food product. Because of the high cost, there is some incentive for unscrupulous producers or processors to adulterate the product. In addition, maple syrup is priced and sold according to grade, with lighter colored syrups worth more than darker syrups. We developed a method to detect artificial decolorization of maple syrup via ion-exchange resins that have been developed for the cane and corn sugar industry. By determining the sodium to chlorine ratio in maple syrup, we are able to detect possible use of ion exchange resins which decolor liquid sugars. Normally, maple syrup has a very low chlorine content. Chlorine is used as an exchange ion in many of the resins, and therefore increases in concentration in the syrup. Sodium levels are also monitored, in order to measure interference by chlorine based cleaning compounds or by road salt use.

Impacts
This research is aimed at ensuring that consumers are able to purchase contaminant-free maple products. In addition, the economics of maple production is preserved by the detection of illegal manipulation of maple syrup color. Purchasers of bulk maple syrup are provided the tools to detect adulteration at the producer level.

Publications

  • No publications reported this period


Progress 10/01/03 to 09/30/04

Outputs
Maple syrup is typically a very pure product, however occasionally various contaminants may be present. This project will examine the points at which contaminants may be introduced, and ways to effectively reduce contaminants by alterations in equipment or management of sugaring operations. Research in progress is examining the efficacy and detectibility of decolorizing ion exchange resins. Artificial decoloring of maple syrup is considered adulteration. It is suspected that ion exchange resins developed for the cane sugar industry are being used to decolor maple syrup, thus increasing the value of the product. Several methods to detect artificial decoloring are being evaluated, with the hope that one or more procedures will be helpful in determining when decoloring has occurred.

Impacts
This research is aimed at ensuring that consumers enjoy contaminant free maple products. In addition, the economics of maple production is preserved by the detection of illegal manipulation of maple syrup color. Purchasers of bulk maple syrup are provided the tools to detect adulteration at the producer level.

Publications

  • No publications reported this period


Progress 07/01/03 to 06/30/04

Outputs
The effect of various taphole disinfectants on sap volume (quantity and timing), taphole closure, and wounding in sugar maple trees were investigated. Paraformaldehyde (PFA) increased the volume of sap produced by prolonging the sap flow season. Alcohol reduced the quantity of sap, probably through rapid taphole drying. Hydrogen peroxide (H2O2) had no detectable effect. Both PFA and H2O2 were detectable in sap for most or all of the sugaring season. PFA, when used in tapholes, was generally found in the maple syrup produced from these trees. Hydrogen peroxide added to sap was generally non-detectable in the syrup, however when H2O2 was added to syrup as a means of "lightening" syrup, it was readily detectable using test strips.

Impacts
This research is aimed at ensuring that consumers enjoy contaminant free maple products. In addition, the economics of maple production is preserved by the detection of illegal manipulation of maple syrup color. Purchasers of bulk maple syrup are provided the tools to detect adulteration at the producer level.

Publications

  • Isselhardt, M., S. Williams, B. Stowe and T. Perkins. 2003. Recommendations for Proper Plate Filter Press Operation. University of Vermont, Agricultural Experiment Station and Extension Miscellaneous Publication, Burlington, Vermont.
  • Perkins, T.D., M.F. Morselli, A.K. van den Berg, and T.R. Wilmot. 2004. Maple Sap and Syrup Chemistry. In: R. Heiligmann and M. Koelling, North American Maple Syrup Producers Manual. Ohio State Press. (in press).


Progress 07/01/03 to 12/31/03

Outputs
Contamination and adulteration of maple syrup are of concern to both the maple industry and consumers of maple products. This research examines a variety of accidental contaminants, as well as suspected adulterants of maple syrup. Lead is commonly found in older maple manufacturing equipment. This research has led to reduced lead levels in maple products. Paraformaldehyde (PFA) was historically used to inhibit microbial growth that impeded late-season sap flows. Investigation has shown that formaldehyde is readily detectable in sap that has been collected using PFA tablets in tapholes. Another taphole disinfectant, denatured alcohol, leaves little residue, but appears to be ineffective in prolonging maple sap flows in the spring. Maple syrup is graded and priced according to color. Research is being conducted to determine the effectiveness and detectability of two decolorizing agents. The first, hydrogen peroxide, is only effective in high doses, however it causes off-flavors in syrup. Further, hydrogen peroxide is readily detectable in sap and syrup for extended periods of time. The second decolorant, ion-exchange resins, are very effective in decolorizing syrups. Three approaches to detecting the use of decolorizing resins are in development.

Impacts
This research is aimed at ensuring that consumers enjoy contaminant free maple products. In addition, the economics of maple production is preserved by the detection of illegal manipulation of maple syrup color. Purchasers of bulk maple syrup are provided the tools to detect adulteration at the producer level.

Publications

  • Isselhardt, M., S. Williams, B. Stowe, and T. Perkins. 2003. Recommendations for proper plate filter press operation. University of Vermont, Agric. Exp. Station/Extension Pamphlet. 4p.