Joseph S. Caldwell

Bio: Joseph S. Caldwell is an academic researcher from United States Department of Agriculture. The author has contributed to research in topics: Ripening & Petiole (botany). The author has an hindex of 5, co-authored 10 publications receiving 50 citations.

The effect of previous storage temperatures on the quality of dehydrated potatoes

Abstract: Potatoes of several varities were stored at 60°, 50°, 40°, and 32°F. When removed from storage the sugar content of those from the two highest temperatures was low, from 40° it was intermediate, and from 32° excessively high. When these potatoes were dehydrated the highest quality was found in those from 60° and 50° storage where the sugar content was low. In those from 40° storage the quality was mostly good to fair, and from 32° the quality was invariably poor to very poor. These last were sweet, soggy, and badly discolored or scorched due to caramelization of much of the excess sugar.

Food processing with added ascorbic acid.

Abstract: Publisher Summary The use of L-ascorbic acid in processing food was reviewed by Bauernfeind in 1953. By that time, several hundred papers had already been published on studies of various applications of this compound in food processing. L-Ascorbic acid, a 6-carbon compound and a water-soluble vitamin also known as vitamin C (for cevitamic acid), exists in both the reduced and the oxidized forms (dehydroascorbic acid) in nature. It is found in all living tissues. Citrus fruits, tomatoes, potatoes, and cabbage are the important natural dietary sources for man, but content varies depending on variety, environmental factors, and processing. L-Ascorbic acid (vitamin C) is added to processed fruit, vegetables, meat, fish, milk, fats, oils, flour, soft drinks, malt beverages, wine, confections, and synthetic foods. It may be added to enhance nutritional value, or to improve keeping qualities, color, stability, palatability, clarity, or baking quality. This chapter looks at ascorbic acid as an added nutrient. The use of L-ascorbic acid to inhibit or prevent undesirable oxidative changes in the processing of foodstuffs has been largely empirical. It discusses ascorbic acid as synergist in fat protection, preventive of fruit browning, preventive of vegetable discolorations, inhibitor of oxidative rancidity in fish, stabilizer of meat color, flour or bread improver, oxygen acceptor in beer processing, reducing agent in wine, oxidation inhibition in dairy products, and other miscellaneous uses. The use of ascorbic acid in a nutrient capacity or as a food processing aid is subject to government regulation in many countries. The status of ascorbic acid addition in each instance of desired use should be determined by consulting the pertinent regulation. A brief review of the regulatory requirements in some countries is given here. This chapter ends with the discussion of L-Ascorbic acid vs. erythorbic acid.

Sugars in peach fruit: a breeding perspective

Abstract: The last decade has been characterized by a decrease in peach (Prunus persica) fruit consumption in many countries, foremost due to unsatisfactory quality. The sugar content is one of the most important quality traits perceived by consumers, and the development of novel peach cultivars with sugar-enhanced content is a primary objective of breeding programs to revert the market inertia. Nevertheless, the progress reachable through classical phenotypic selection is limited by the narrow genetic bases of peach breeding material and by the complex quantitative nature of the trait, which is deeply affected by environmental conditions and agronomical management. The development of molecular markers applicable in MAS or MAB has become an essential strategy to boost the selection efficiency. Despite the enormous advances in 'omics' sciences, providing powerful tools for plant genotyping, the identification of the genetic bases of sugar-related traits is hindered by the lack of adequate phenotyping methods that are able to address strong within-plant variability. This review provides an overview of the current knowledge of the metabolic pathways and physiological mechanisms regulating sugar accumulation in peach fruit, the main advances in phenotyping approaches and genetic background, and finally addressing new research priorities and prospective for breeders.

Some Aspects of the Biochemistry of Apple and Pear Fruits

Abstract: Publisher Summary This chapter presents the overall biochemical and physiological picture of the apple and pear as it is today to serve as a “clearing of the ground” for the work that lies ahead. As with other fields of biochemistry, perhaps the greatest hope for rapid progress in the future lies in the use of isotopic tracer techniques—techniques that are only just beginning to be explored in the field of apples and pears. Some reference to auxin production has been considered. Some analytical results obtained for fruit juices have been included. In general, the compounds present in these unfermented juices are representative of the soluble constituents of the whole fruit. The chapter tabulates, in broad general terms, a picture of the biochemical pattern of the mature fruit. The most remarkable fact is the relatively small variation in the nitrogen, acid, sugar, and pectin content of the mature fruit. In this overall picture, the most noticeable varietal difference is in the “tannin” fraction where cider and perry fruits exhibit a high relative content. The chapter deals with each main group of constituents during development of the fruit on the tree and during its senescence after harvesting.

The nitrogen nutrition of green plants. II

Abstract: Nitrate reduction may occur in robts, in storage organs and in stems and leaves. At least in underground organs nitrate reduction occurs in darkness with oxidation of carbohydrates or their derivatives. Burstrom (36) concludes that in wheat leaves nitrate reduction is a photosynthetic process that does not occur in the absence of light, although ammonium was elaborated in darkness in the leaves of wheat. If a liberal supply of oxygen is available in the nutrient substrate, and of cations, including particularly potassium, and if there is adequate absorption of other essential elements, then ammonium is more rapidly utilized by plants than nitrate. However, ammonium nutrition typically results in relatively rapid depletion of carbohydrate reserves if conditions are not favorable for carbohydrate accumulation. It is pointed out that environmental influences, such as low temperature or a high concentration of salts in the nutrient substrate, including even a high content of nitrogen, may lead to carbohydrate accumulation and deficiency of elaborated nitrogen in the plant. Examples are given of experimental results apparently pointing to an intimate relation between carbohydrates and specific factors or hormones associated with the inception of flower primordia and root development. Effects on various crop plants of nitrogen or carbohydrate deficiency are discussed along with methods by which the plant may be employed as guide in nitrogen fertilization using carbohydrate content as the primary index.

Quantitative and Qualitative Changes in Sugar Content of Peach Genotypes [Prunus persica (L.) Batsch.]

Abstract: Fruit of four clingstone peach (Prunus persica (L.) Batsch.) seedling populations, 54 advanced selections, and the cultivars Allgold and Goldilocks were analyzed for sugar content, soluble solids concentration (SSC), and acidity. Sucrose, glucose, fructose, and sorbitol were identified and quantified by high pressure liquid chromatography (HPLC) analysis. Variation was found for all the sugars between the seedling populations. Comparison of the means for the advanced selections with 'Goldilocks' indicates that progress has already been made toward selection for a sweeter peach. Glucose, fructose, sorbitol, SSC, and acidity (citric) differed significantly for two harvest years, while sucrose and total sugar concentrations showed no significant yearly variation. A fruit maturity study revealed no significant changes in SSC, percentages of glucose, fructose, and total sugar during ripening on the tree. Acidity and percent sorbitol decreased, while the sugar : acid ratio and percent sucrose increased with increasing maturity. Broad- sense heritability of SSC, acidity, and sugar : acid ratio bad values >0.72, while values for individual sugars and total sugars were much lower. Transgressive segregation for each sugar was found in seedling populations.