Monitoring of soybean germination process by near-infrared spectroscopy

Soybean seeds were germinated on an industrial scale after soaking for 0–56 h to produce a special additive for food industrial use. The germination process of three soybean varieties was monitored with near-infrared (NIR) spectroscopy based on changes in the amount, status, or character of the water. This paper evaluates the “waterless” NIR spectra of sound, germinated, and heat treated seeds to try to follow the fine details of the germination process. The germination process was analysed with the help of cluster analysis (CA), principal component analysis (PCA), and polar qualification system (PQS) as statistical and chemometric methods. PCA proved to be the most sensitive spectrum evaluation method to follow the fine details of germination. The applied NIR method is suitable for non-destructively, real-time monitoring of the non-linear nature of germination.

Bread preparation by partial replacement of wheat by germinated sorghum

Published literature shows significant impact of sorghum type and flour on end-product quality, while demonstrating paucity in the studied varieties with respect to processing aspects (such as bread making) despite of enormous accessions available worldwide. Limited studies have reported usage of germinated flour for the above said purpose. The present study thus aimed at mitigating these gaps by utilizing results of sorghum (HJ-513) germination (Day 1-5) and flour derived from optimized condition (Day 3 as identified by partial least square analysis) to develop a composite functional bread (partial replacement of wheat). The germination process enhanced the total phenolics compounds (TPC, till day 3), water (14.01%) and oil absorption capacity (25.97%) while reducing the bulk density (760.99-644.69 kg/m³). This demonstrated increased potential of sorghum flour for development of bakery and confectionery products. The process also affected the pasting properties, total flavonoids compounds (TFC) and DPPH (2, 2-diphenyl-1-picrylhydrazyl) significantly (p < 0.05). The bread developed from partial replacement (10% and 20%) of refined wheat flour by sorghum was hard and darker than the control wheat bread. The bread developed at 20% was more dense and porous than the bread developed with 10% replacement. Specific volume of bread at 10% replacement was found higher than at 20% replacement. The study reports effective utilization of germinated sorghum flour for development of composite-functional bread without incorporation of any other additives/improvers. Future research however is warranted in the field to further increase the replacement of wheat flour by germinated sorghum flour to develop gluten free bread.

Near infrared and fluorescence spectroscopic methods and electronic nose technology for monitoring foods

There is a clear need for application of proper methods for measuring food quality and safety in the globalized food-webs. Numerous instrumental methods have been established in the course of the 20th century and are developing further, together with data analysis techniques, for such purposes. Among them, near-infrared and fluorescence spectroscopic methods and chemical sensor arrays called electronic noses show particular promise for rapid, non-destructive, non-invasive and cost-effective ways for assessing changes and enhancing control during processing and storage of foods. Their key advantages as analytical tools are 1) their relatively high speed of analysis, 2) the lack of a need to carry out complex sample preparation or processing, 3) their relatively low cost, and 4) their suitability for on-line monitoring or quality control. The present survey attempts to demonstrate examples from the above areas, limiting itself mainly to monitoring some quality indices which contribute to the functionality or acceptability of foods as affected by alternative processing technologies, or loss of freshness/microbial safety, or developing spoilage during storage and marketing. These instrumental methods are correlative techniques: they must be calibrated first against (traditional) reference properties, and the instrumental data are evaluated with the help of chemometric methods. Near-infrared (NIR) spectroscopy can be used in either the reflectance or the transmittance mode. NIR spectra transformed to mathematical derivatives allows subtle spectrum changes to be resolved. Selected examples from the extensive NIRS literature relate to assessment of the quality of frozen fish, predicting cooking loss of chicken patties, detecting complex physico-chemical changes of minced meat as a function of the intensity of high hydrostatic pressure treatment, comparing changes of NIR spectrometric “fingerprints” caused by gamma radiation or high pressure pasteurization of liquid egg white. Changes of NIR spectra reflect several parameters which suit the evaluation of loss of freshness, and onset of spoilage of various foods. NIR spectroscopy shows an application potential for rapid detection of bacterial or mould contamination. It may serve as a tool for detecting initial stages of mobilization processes during germination of cereal grains, or even for GMO screening. Spectrofluorometic measurements have shown potential, e.g. to monitor lipid oxidation and development of meat rancidity, to differentiate between raw and processed milks, and to monitor fish and egg freshness. Electronic noses containing chemical sensor arrays offer a rapid method for evaluation of head-space volatiles of food samples, important for characterizing quality and safety. Such gas sensors may be able to classify storage time, and determine spoilage, either earlier or at the same time as the human senses, or “sniffing out” bacterial pathogens or (toxigenic) fungal growth on certain foods. Electronic nose sensing is also a promising method for detecting quality changes of fruit- and vegetable products non-destructively. In relation to some examples to be presented in the paper, certain software developments as qualitative classification tools made by Hungarian scientists will be pointed out.