We do vitamin and other compound analysis of fresh fruits & vegetables. Every extraction method we know impacts the organic compounds. Does anyone know a source for reference materials on extraction methods?

I found this book. It may be useful to you.

Extraction of Organic Analytes from Food : A Manual of Methods

by R Self

Publisher: Royal Society of Chemistry; 1 edition (July 1, 2005)

ISBN: 0854045929

here is the book description

Book Description
This book is designed as a laboratory manual of methods used for the preparation and extraction of organic chemical compounds from food sources. It offers ideas on how to facilitate progress towards the total automation of the assay, as well as proposing assays for unknowns by comparison with known methods. Beginning with an introduction to extraction methodology, Extraction of Organic Analytes from Foods then progresses through sample preparation, extraction techniques (partition, solvation, distillation, adsorption and diffusion) and applications. Subject indices for the applications are organised by commodity, method, chemical class and analyte, and provide useful examples of references from the literature to illustrate historical development of the techniques. Examples of methods that have been compared, combined or used in collaborative trials have been correlated and used to form the beginnings of a database that can be expanded and updated to provide a laboratory reference source. Logically structured and with numerous examples, Extraction of Organic Analytes from Foods will be invaluable to practising food analysts as both a reference and training guide. In addition, the introductory sections in each chapter have been written with food science and technology students in mind, making this an important title for academic libraries.

I found another one

Modern Analytical Methodologies in Fat- and Water-Soluble Vitamins

by Won O. Song (Editor), Gary R. Beecher (Editor), Ronald R. Eitenmiller (Editor)

Publisher: Wiley-Interscience; 1 edition (February 25, 2000)
Language: English
ISBN: 0471179426

Here is another one:

Extraction Methods in Organic Analysis By Alan John Handley By Alan John Handley
Published 1999
CRC Press
308 pages
ISBN 0849397405

This volume covers conventional and contemporary techniques of extraction and sample preparation, crucial elements in accurate analysis. Each chapter covers some background theory, the available instrumentation and the strengths and weaknesses of the method. Key applications are then addressed.