The physical chemistry characteristics of honey are directly related to floral origin and, as a result, to the production region. There are some available methods that can determine the botanical or geographical origin of honey such as the free amino acids profile analysis. This paper reports data on the free amino acid composition, determined by reversed-phase high-performance liquid chromatography UV detection on 56 honey samples from three different Argentine regions, with characteristic apiarian flora. To evaluate if the quantified amino acid could be used to verify the geographical or botanical origin of honey, statistical analyses were performed. The cluster analysis showed that samples were grouped in clusters related to sampling regions and more strictly to apiarian flora around apiaries. Each cluster appears associated, in accordance with the principal component analysis, to high or low concentrations of different amino acids.

In this work, a new enzymatic method is proposed to evaluate the degree of starch gelatinization in starchy food and feed. The procedure developed is based on the fact that the gelatinization process enhances the chemical reactivity of inert starch granules towards amylolytic enzymes. Aqueous suspensions of maize starch were treated at different temperatures to obtain different degrees of gelatinization, from 25 °C (control without gelatinization) until 95 °C. Heated samples were then incubated with a glucoamylase. The enzymatic activity was measured by the glucose released during the digestion time by using a standard glucose oxidase method. The initial velocity value of the enzymatic reaction (Vi) was selected as the parameter to quantify the degree of starch gelatinization (DG). Changes in granule morphology and the starch available for hydrolysis were evaluated by photomicrographs. The new method was standardized and compared with DSC and viscosity measurements in order to check its efficiency, considering the DG observed by photomicrographs. A good agreement was observed between the DG calculated by Vi and by DSC (correlation coefficient r = 0, 97), thus Vi reflect the degree of starch gelatinization as well as DSC. These results show that the developed enzymatic procedure is an effective method to evaluate the DG in starchy foods and feeds.

Aflatoxin contamination is one of the main factors affecting peanut seed quality. One of the strategies to decrease the risk of peanut aflatoxin contamination is the use of genotypes with resistance to Aspergillus infection. This laboratory study reports the resistance to Aspergillus infection and aflatoxin contamination of six peanut genotypes inoculated with 21 Aspergillus isolates obtained from the peanut production region of Cordoba, Argentina. The resistance was investigated in the seed coat and cotyledons of three resistant genotypes (J11, PI 337394, and PI 337409) and three breeding lines (Manfredi 68, Colorado Irradiado, and Florman INTA) developed at the Instituto Nacional de Tecnologia Agropecuaria (INTA), Manfredi Experimental Station, Cordoba, Argentina. Resistance to fungal colonization and aflatoxin contamination was found to be associated with seed coat integrity in the PI 337394, PI 337409, and J11 genotypes, whereas the INTA breeding lines such as Colorado Irradiado showed a moderate resistance and the Manfredi 68 and Florman INTA genotypes the least resistance. Furthermore, another type of resistance associated with cotyledons was found only in the PI 337394 genotype.

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Aspergillus flavus and A. parasiticus are aflatoxin-producing fungi that can infect peanut seeds in field crops. An association between A. parasiticus proteolytic enzyme activities and peanut fungal infection was examined. For this study, a model of inductive and non-inductive culture media to produce A. parasiticus extracellular protease before infection was used. These A. parasiticus cultures were used to infect peanut seeds of cultivars resistant and susceptible to aflatoxin contamination. Peanut seeds of both cultivars exposed to fungi grown on casein medium (inductive medium) showed higher internal and external infection and a higher fungal protease content than those observed on potato dextrose agar (PDA) and sucrose medium (non-inductive media). A further study showed higher fungal colonisation and aflatoxin contamination in seeds of the resistant cultivar preincubated with Aspergillus extracellular proteases than in those incubated without proteases. Moreover, protease activities affected the viability of noninfected resistant cultivar seeds, inhibiting germination and radicle elongation and enhancing seed tissue injury. The results strongly suggest that protease production by A. parasiticus is involved in peanut seed infection and aflatoxin contamination resulting in seed tissue damage, affecting seed viability and facilitating the access of fungi through the testa. The analysis of fungal extracellular proteases formed on peanut seed during infection showed that A. flavus and A. parasiticus produced metallo and serine proteases; however, there were differences in the molecular masses of the enzymes between both species. The greatest activity in both species was by serine protease, that could be classified as subtilase.