Ultrasound-assisted annealing treatment to improve physicochemical and digestive properties of banana flour

BACKGROUND

Banana flour can provide a solution to people with gluten intolerance, as it is gluten-free. Native banana flour may have limited functionality in certain applications. In this study, banana flour was modified by ultrasonic (US) and annealing (ANN) treatments at four incubation time spans, namely 12, 24, 36 and 72 h, separately or combined sequentially (US-ANN) to enhance the physicochemical and digestive properties.

RESULTS

US led to exposed granular surfaces and damaged non-starch components. Both treatments, at extended incubation time, increased crystallinity, resulting in a narrower starch gelatinization temperature range. The swelling power was significantly lower for ANN and US-ANN compared to US alone, providing a delay of gelatinization temperature. However, none of the treatments affected the gelatinization enthalpy. Furthermore, US increased peak viscosity, breakdown, final viscosity and setback whereas the opposite results were obtained for ANN and US-ANN. Additionally, US prior to ANN significantly increased the resistant starch (RS) content for annealing times over 24 h, especially for the US-ANN treatment for 72 h, which provided the highest RS content (49.3%) compared to ANN treatment for 72 h (44.0%) and native flour (36.3%).

CONCLUSIONS

US prior to ANN treatment offers an alternative method to improve the functional and digestive properties of banana flour, extending the range of applications. © 2024 Society of Chemical Industry.

Nutritional analysis of rice landraces from southern Odisha, India

Rice landraces conserved by tribal farmers are important for their nutritional richness. Landraces are rich in essential amino acids, vitamins, anthocyanins, and flavonoids useful to cure noncommunicable diseases and metabolic disorders. A study was carried out with 10 rice landraces from the tribal-dominated belt of Southern Odisha to investigate grain nutrition, proximate composition, and vitamin and mineral contents. The protein content of the landraces was higher (>6 g/100 g) and the fat content was lower (<0.6 g/100 g) than popular Indian rice varieties. The mean nutrient content of 10 rice landraces was as follows: protein 6.3 ± 0.313 g/100 g, total dietary fiber 1.6 ± 0.094 g/100 g, fat 0.536 ± 0.008 g/100 g, ash 10.514 ± 6.753%, and total sugar 77.18 ± 2.118 g/100 g. The high genotypic coefficient of variation (GCV) was observed for alkali spreading value (31.11%), capacity of grain hydration (52.705), index of hydration (171.439), moisture (46.343%), and vitamin B2 (23.994%) in rice landraces. Few landraces had superior iron content: Kalamalli (1.49 mg/100 g), Kandulakathi (1.42 mg/100 g), and Dudhamani (1.39 mg/100 g) compared to popular Indian rice varieties. Tikichudi had highest moisture (19%) and fat (0.53 g/100 g) content, which signifies the taste quality of rice. Kanakchudi exhibited the highest fiber content (1.8 g/100 g) and ash content (22.80%). Kalamalli contained higher zinc (0.49 mg/100 g), iron (1.49 mg/100 g), potassium (108.33 mg/100 g), magnesium (78.33 mg/100 g), and phosphorus (125.00 mg/100 g), whereas Muktabali was found to have higher Ca (3.88 mg/100 g) and Baunsidubraj exhibited higher niacin (4.9 mg/100 g). The indigenous landraces Kalamalli, Kandulakathi, and Dudhamani had considerably high iron content, whereas Kalamalli, Baunsidubraj, and Muktabali possessed less phytic acid in comparison with existing varieties and other landraces reported from various states of our country. Landraces Kalamalli, Kanakchudi, Tikichudi, and Muktabali from southern Odisha, India, represented nutritionally better genetic pool for future rice improvement.

Evaluation of commercial rice grains present in the Amman market

Rice is a staple food that contributes to significant energy intake. Jordan relies on importing to provide the market with the required quantities of rice. Different varieties from different sources with various qualities are available in the market. This study aimed to evaluate the quality of rice available in the markets in Amman city-Jordan. Twenty-five brands (three samples from each brand) were collected. Samples were evaluated regarding chemical composition, dimensions before and after cooking, percentage of different defects, pasting profile (pasting temperature, peak viscosity, peak time, trough, and final viscosity), whiteness, transparency, and milling degree. All rice samples tested comply with the Jordanian standard except for chalky kernels (four brands), heat-damaged kernels (one brand), and insect infestation (two brands). All samples that did not fulfil the Jordanian specifications were from the long-grain rice. Medium-grain rice has higher whiteness, transparency, milling degree, moisture, starch, peak viscosity, trough, and final viscosity than long-grain rice. On the other hand, long-grain rice has a higher protein, pasting temperature, and peak time. There were significant differences in pasting and chemical composition parameters within the two groups of grain sizes. The average elongation ratio for all samples was 1.57 ±0.14, with significant differences between different brands. Due to the higher pasting temperature and peak time, long-grain rice requires more energy during cooking than medium-grain rice.

Analysis of apparent amylose content of market milled rice via digital image photometry using a smartphone camera

Apparent amylose content (AC) of market milled rice was analyzed through digital image photometry (DIP) utilizing a smartphone camera and a free-access software (ImageJ). The DIP-AC method was validated using seven test samples and applied to a set of 17 commercially available milled rices varying in AC. A light box was constructed to accommodate a cuvette and a smartphone while ImageJ was used for digital image analysis towards quantifying AC. Smartphone camera settings were also optimized using the red, green, and blue (RGB) values of the digital images of amylose-iodine blue solutions. ISO 100 combined with shutter speed 1/640 was the optimum and most suitable settings combination when B values were used to generate calibration curves yielding a high degree of linearity (r = 0.995–0.998). Validation showed the DIP-AC method to be accurate based on the conventional ultraviolet–visible (UV-vis) spectrophotometric AC assay. It was also found to be repeatable and precise for non-waxy rice samples only, yielding RSD values below 7% among all replications made within one day and across different days. With the optimized DIP-AC assay, limits of detection and quantitation of AC that is capable of iodine binding at alkaline pH and influencing cooked rice texture, were 0.2% and 0.4% (milled rice basis at 12–14% moisture), respectively. The reported DIP-AC method can be a reliable and accurate assay for determining AC of non-waxy milled rice alternative to UV–vis spectrophotometry. Further refinement of the DIP-AC method is warranted to improve precision in measuring AC of milled waxy rice.

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Smartphone camera was used in digital image photometry of rice apparent amylose content (AC).

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Spectrophotometric AC of non-waxy milled rice was similar with digital image photometric AC.

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High repeatability and reproducibility were obtained for digital image photometric AC assay.

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Digital image photometric method for AC can accurately measure AC of non-waxy market milled rice.

Resistant starch levels and in vitro starch digestibility of selected cooked Philippine brown and milled rices varying in apparent amylose content and glycemic index

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Resistant starch content of rice correlates well with apparent amylose content.

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Cooked brown rices generally have more resistant starch than cooked milled rices.

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Resistant starch, hydrolysis index, and glycemic index of rice are all correlated.

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In vitro starch digestibility of cooked milled rice is greater than brown rice.

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Starch digestibility properties of cooked rice are vital in human nutrition and health.

Resistant starch (RS) content, starch digestibility, and hydrolysis index (HI) were analyzed in vitro for four selected Philippine rice varieties varying in apparent amylose content (AC) and glycemic index (GI), in cooked brown and milled rice forms. Starch digestibility curves were studied in relation to AC and reported GI values. Brown and milled rices of Improved Malagkit Sungsong 2 (IMS2), NSIC Rc160, IR64, and PSB Rc10 were cooked on separate beakers placed in automatic electric rice cookers and based on pre-determined water:rice ratios. RS levels of cooked milled rices ranged from 0.15 to 0.99% (mean = 0.45%). Their corresponding cooked brown rices had RS contents ranging from 0.24 to 1.61% (mean = 1.05%), with PSB Rc10 having the highest levels in both forms. HI ranged from 59.3 to 102.2%, with the highest noted for the waxy rice, IMS2, while corresponding brown rices had significantly lower HI spanning 49.2–66.9%. Previously reported GI values of these varieties were positively correlated with HI and estimated GI in this study. RS and non-resistant starch levels, and HI were highly correlated with AC. In vitro starch digestibility studies, as related to AC and GI, may be useful in screening for rice grain and nutritional properties aimed at developing new varieties with desirable quality and enhanced nutritional and functional properties.

Nutritional and functional properties changes during facultative submerged fermentation of gadung (Dioscorea hispida Dennst) tuber flour using Lactobacillus plantarum

This work aims to examine the influence of flour concentrations (5%–25% w/v), inoculum loading (2.5%–15% v/v), and fermentation time (0–144 h) on the nutritional and functional properties of gadung (Dioscorea hispida Dennst) tuber flour. The flour was microbiologically treated through facultative submerged fermentation using Lactobacillus plantarum. The carbohydrate, lipid, protein, fiber and ash contents were reduced by fermentation, while moisture content was increased. In general, the swelling power and the solubility of fermented flour were below those of the native flour. Carboxyl group content increased with fermentation time, whereas no clear trend was found for carbonyl group. The amylose content of the fermented flour was larger than that of the native flour, which most probably was due to the depolymerization of amylopectin branches to form new amylose-like molecules. The best fermentation conditions were flour concentration of 10% (w/v), inoculum loading of 5% (v/v), and fermentation for 48 h.

Rice quality: How is it defined by consumers, industry, food scientists, and geneticists?

BACKGROUND

Quality is a powerful engine in rice value chain upgrading. However, there is no consensus on how "rice quality" should be defined and measured in the rice sector.

SCOPE AND APPROACH

We adopt a Lancasterian definition of rice quality as a bundle of intrinsic and extrinsic attributes. We then review how rice quality is (i) perceived and defined by consumers and industry stakeholders in rice value chains in Southeast and South Asia; (ii) measured and defined by food technologists; and (iii) predicted through genetics.

KEY FINDINGS AND CONCLUSIONS

Consumers are heterogeneous with respect to their perceived differentiation of rice quality among regions, countries, cities, and urbanization levels. Premium quality is defined by nutritional benefits, softness and aroma in Southeast Asia, and by the physical appearance of the grains (uniformity, whiteness, slenderness), satiety, and aroma in South Asia. These trends are found to be consistent with industry perceptions and have important implications for regional and national breeding programs in terms of tailoring germplasm to regions and rice varieties to specific local market segments. Because rice is traded internationally, there is a need to standardize definitions of rice quality. However, food technologists have not reached unanimity on quality classes and measurement; routine indicators need to be complemented by descriptive profiles elicited through sensory evaluation panels. Finally, because rice quality is controlled by multiple interacting genes expressed through environmental conditions, predicting grain quality requires associating genetic information with grain quality phenotypes in different environments.

Improving Rice Grain Quality: State-of-the-Art and Future Prospects

Rice grain quality encompasses complex interrelated traits that cover biochemical composition, cooking, eating, nutritional, and sensory properties. Because rice endosperm is composed mainly of starch, rice grain quality is traditionally defined by characterizing starch structure and composition, which is then subsequently correlated with functional properties of the grain. The current proxy tests routinely used to describe rice grain quality preferences are rather limited to the estimation of apparent amylose content, gelatinization temperature, and gel consistency. Additional tests that characterize starch property, viscoelasticity, grain texture, and aroma are also employed in more advanced laboratories. However, these tests are not routinely applied in breeding programs to distinguish cooking quality classes to reflect evolving consumer preference and market demand. As consumer preferences in Asia and all over the world are diverse due to varied demographics and culture, defining uniform attributes to capture regional grain quality preferences becomes more challenging. Hence, novel and innovative proxy tests are needed to characterize rice grain quality to meet the demand for consumer preferences of commercially-released cultivars. In this chapter, the current methods employed in rice grain quality monitoring are succinctly reviewed. Future prospects for improvement are identified, introducing cutting edge technologies that can facilitate high-throughput screening of rice diversity panels and breeding lines. Aside from addressing the requirements for quality improvement in the traditional inbred rice breeding programs, we also tackled the need to enhance grain quality in the hybrid rice sector.

Developing a framework of gastronomic systems research to unravel drivers of food choice

Nutritional and dietary interventions and the introduction of novel food products and ingredients require a thorough understanding of the drivers of food choice, which are embedded in local context and culture. We developed a framework of "gastronomic systems research" (GSR) to understand culture-specific consumer food choice, and contextualise it to a target population of urban, middle- to high-income Filipino consumers to assess the domestic niche market potential of traditional rice varieties in the Philippines. The GSR framework was contextualised through expert elicitation involving chefs and nutritionists, and validated through a consumer survey conducted during a food exposition. Using the GSR framework, we determined indicative rice consumption patterns of the target population and the specific rice quality attributes they require for specific rice-based dishes and rice consumption occasions. The GSR framework also reveals possible entry points for nutritional and dietary interventions and the introduction of novel food products and ingredients. The GSR framework, therefore, has the potential to aid policymakers and food value chain stakeholders in designing culture-sensitive and context-appropriate interventions not only to help consumers improve their diets, but also to help farmers access niche markets for novel food products and ingredients and thereby improve their livelihoods and preserve cultural heritage.