Research advancements in optical imaging and spectroscopic techniques for nondestructive detection of mold infection and mycotoxins in cereal grains and nuts.

Cereal grains and nuts are represented as the economic backbone of many developed and developing countries. Kernels of cereal grains and nuts are prone to mold infection under high relative humidity and suitable temperature conditions in the field as well as storage conditions. Health risks caused by molds and their molecular metabolite mycotoxins are, therefore, important topics to investigate. Strict regulations have been developed by international trade regulatory bodies for the detection of mold growth and mycotoxin contamination across the food chain starting from the harvest to storage and consumption. Molds and aflatoxins are not evenly distributed over the bulk of grains, thus appropriate sampling for detection and quantification is crucial. Existing reference methods for mold and mycotoxin detection are destructive in nature as well as involve skilled labor and hazardous chemicals. Also, these methods cannot be used for inline sorting of the infected kernels. Thus, analytical methods have been extensively researched to develop the one that is more practical to be used in commercial detection and sorting processes. Among various analytical techniques, optical imaging and spectroscopic techniques are attracting growers' attention for their potential of nondestructive and rapid inline identification and quantification of molds and mycotoxins in various food products. This review summarizes the recent application of rapid and nondestructive optical imaging and spectroscopic techniques, including digital color imaging, X-ray imaging, near-infrared spectroscopy, fluorescent, multispectral, and hyperspectral imaging. Advance chemometric techniques to identify very low-level mold growth and mycotoxin contamination are also discussed. Benefits, limitations, and challenges of deploying these techniques in practice are also presented in this paper.

Emerging nondestructive techniques to quantify the textural properties of food: A state-of-art review.

Texture is an important sensory attribute that drives consumer acceptance of any food material. In recent times consumers' demand for high-quality food urges food industries to provide food with consistent textural properties. However, texture measurement not just requires a trained sensory panel but also a considerable amount of time and effort. On the flip side, human observation could be subjective hence repeatability of the result may not be ensured and/or relied on. Contrary to that, objective methods for texture measurement are reliable and consistent, but are not suitable for in-line application and also destructive in nature. The mentioned crisis has made industries opt for nondestructive texture analysis techniques. In the past decade, considerable research has been carried out on nondestructive texture analysis methods such as micro-deformation, and acoustic and optical techniques, showing feasibility for in-line applications. The current review focuses on the working principles and most recent applications of nondestructive techniques for texture analysis of food products. Moreover, a detailed review of contact and noncontact-type texture measurement has been presented in this article. The literature survey is concluded with future research aspects and challenges involved in the commercialization of the nondestructive texture analysis techniques.

Effect of pulsating microwave treatment on wheat parboiling: Comparative assessment and structural characterization.

The current study focusses on investigating the impact of pulsating microwave (MW) treatment to develop an efficient wheat parboiling method through comparative assessment with conventional parboiling. Three independent variables i.e., MW power level, effective treatment time, and pulsating mode on-off combination were tried for the process optimization. Higher moisture gain was observed during pulsating MW treatment, irrespective of the power level. The optimised gelatinization was obtained at 900 W power level and 9 min treatment time with on-off combination of 30 s -120 s considering specific energy absorption, water quality and degree of gelatinization. The microwave parboiled sample showed no major difference in molecular rearrangement, surface morphology and starch deformation as compared to the conventionally parboiled (CP) samples analysed using XRD, SEM, and FTIR study, whereas slight variation in protein conformations were noticed. This technological and structural study revealed that the proposed method can effectively replace the CP method.

Trichothecenes in food and feed: Occurrence, impact on human health and their detection and management strategies.

Trichothecenes (TCNs) are the mycotoxins produced by many fungal species such as Fusarium, Myrothecium, and Stachybotrys and pose a considerable health risk. Based on their characteristic functional moieties, they are divided into four categories: Type A (T-2, HT-2, diacetoxyscirpenol (DAS), harzianum A, neosolaniol (NEO) and trichodermin), Type B (deoxynivalenol (DON), nivalenol (NIV), trichothecin and fusarenon X), Type C (crotocin) and Type D (satratoxin G & H, roridin A and verrucarin A) with types A and B being the most substantial. TCNs cause growth retardation in eukaryotes, suppress seedling growth or regeneration in plants and could be a reason for animal reproductive failure. Due to the increased frequency of occurrence and widespread distribution of TCNs in food and feed, knowledge of their sources of occurrence is essential to strategise their control and management. Hence, this review provides an overview of various types and sources of TCNs, the associated biosynthetic pathways and genes responsible for production in food and feed. Further, various processing and environmental effects on TCNs production, detection techniques and management strategies are also briefly outlined.

Quantitative Analysis of Major Phytochemicals in Orthodox tea (Camellia sinensis), Oxidized under Compressed Air Environment.

This study describes major changes in phytochemical composition of orthodox tea (Camellia sinensis var. Assamica) oxidized under compressed air (CA). The experiments for oxidation were conducted under air pressure (101, 202, and 303 kPa) for 150 min. Relative change in the concentrations of caffeine, catechins, theaflavins (TF), and thearubigins (TR) were analyzed. Effect of CA pressure was found to be nonsignificant in regulating caffeine concentration during oxidation. But degradation in different catechins as well as formation of different TF was significantly affected by CA pressure. At high CA pressure, TF showed highest peak value. TR was found to have slower rate of formation during initial phase of oxidation than TF. Even though the rate of TR formation was significantly influenced by CA, a portion of catechins remained unoxidized at end of oxidation. Except caffeine, the percent change in rate of formation or degradation were more prominent at 202 kPa.