The effect of the amylose content and milling fractions on the physico-chemical features of co-extruded snacks from corn

Unlocking the potential of pasting properties to predict extrudate characteristics of corn grits blends with high amylose corn starch, potato starch, or rice flour

The development of new production lines of extruded ready-to-eat (RTE) snacks often results in high losses of edible food due to the trial-and-error approach in industry. Being able to predict extrudate characteristics of new formulations before having to run trials on industrial scale would be beneficial for reducing waste and having a more efficient development process. With this study, the correlation between pasting properties of seven blends of flours/starches and extrudate characteristics was investigated (100% corn grits, 25% and 50% replacement of corn grits with high amylose starch, potato starch, and rice flour). The predictive power of pasting characteristics on extrudate's moisture content, water absorption and solubility index, sectional expansion index (SEI) and hardness was studied. Results indicated the potential of predicting SEI, water solubility index (WSI), and water absorption index (WAI) of RTE-snacks. WSI and WAI were, respectively, negatively correlated with peak temperature (R2  = 0.897), and positively with peak temperature and positively with trough viscosity (R2  = 0.855). One can conclude that the rheometer can be a useful tool to gain insight into the characteristics of the extrudate, although further research with enlargement of the dataset is necessary to make the rheometer effectively deployable for potentially other extrudate characteristics.

Effect of enrichment of rice snacks with pulse seed coats on phenolic compound content, product features and consumer hedonic response

This study investigated the impact of seed coats from peas (PC) and chickpeas (CC) (at 15 % and 30 % levels) on rice-based co-extruded snacks. Using PC and CC reduced the content of soluble (29 %) and cell-wall bound phenolic acids (21 %), but it enhanced the amount and the profile of flavonoids of rice-based snacks (up to 16 times with PC), resulting in significantly higher antioxidant activity (134 %). Snacks with 15 % CC showed a higher section area (about 335 versus 191 mm2) and a lower average pore radius (20.1 versus 23.9 mm) than PC-snacks; however, such features did not affect either texture or porosity. At 30 % level, PC resulted in a more porous structure (porosity: 73.1 versus 66.7 %) with smaller pores (17.2 versus 27.3 mm) and high firmness (55.9 versus 40.1 N). Consumers' acceptability evaluation revealed that samples containing pulse seed coat were comparable and preferred to the control (i.e., 100 % polished rice).

High-amylose and Tongil type Korean rice varieties: physical properties, cooking behaviour and starch digestibility

The National Institute of Crop Science, Rural Development Administration (RDA) of Korea is presently developing new rice varieties suitable for producing Western rice-based foods, such as risotto, a well-known Italian-style product. The study considered different milled rice from five Tongil-type and six Japonica-type varieties. Besides the biometric properties, cooking behaviour, starch properties, and in vitro digestibility of Korean rice samples were compared with those of the 'Carnaroli' Italian variety. The physicochemical traits of the Korean varieties extended over a vast range; the amylose content stood out (from 13.0 to 41.7%), influencing the hardness and stickiness of cooked samples, and their starch digestibility. Although none of the Korean varieties seemed to guarantee cooking performances for risotto similar to the 'Carnaroli' one, 'Saemimyeon' and 'Shingil' cvs were judged the best for this purpose up-to-now.

High-amylose starch: Structure, functionality and applications

Starch with a high amylose (AM) content (high AM starch, HAS) has attracted increasing research attention due to its industrial application potential, such as functional foods and biodegradable packaging. In the past two decades, HAS structure, functionality, and applications have been the research hotspots. However, a review that comprehensively summarizes these areas is lacking, making it difficult for interested readers to keep track of past and recent advances. In this review, we highlight studies that benefited from rapidly developing techniques, and systematically review the structure, functionality, and applications of HAS. We particularly emphasize the relationships between HAS molecular structure and physicochemical properties.

Acceptance of New Formulations of Extruded Gluten Free Snacks Based on Pulse Flours by Spanish Millennial Consumers

Nowadays, the food industry has developed novel gluten free extruded snack type products made from pulses, which could be good candidates to promote pulse consumption as a sustainable food product, while also satisfying the consumer’s demand. Snack type products are a large part of the young people’s diets and impact health outcomes, so it is essential to offer them snacks with a better nutritional profile. In this study, 81 Spanish millennial consumers tasted “in situ” six different gluten free snacks based on pulse flour (lentil and chickpea) marketed in Spain. The aim of the present study was: (a) to evaluate the Spanish millennial consumers’ acceptance level of new pulse snack type products; (b) to evaluate the segmentation of the millennial consumers and understand the difference between the segments; (c) to evaluate the potential relationship between their nutrition food labelling and consumers’ acceptance. In general, the lentil formulations (with more protein, more fat and less fiber) obtained higher scores than those of the chickpea. In addition, a multidimensional statistical analysis, preference mapping, and a statistical analysis of agglomerative hierarchical clustering were performed. Consumers were grouped into three clusters based on their preferences, allowing a detailed study of consumer acceptance of the selected snacks. Cluster 1 like less the samples with less salt, and, on the contrary, these samples were preferred by Cluster 3. Cluster 2 is a group who like lentil snacks, regardless of their flavoring. It was observed that the consumer segments differ at least in their preference for saltiness. The findings of this study also showed that the nutritional composition of the analyzed snacks (as appears in nutrition labelling) was associated with Spanish millennial consumers’ acceptance and could provide valuable information to develop new snacks targeted at specific market niches, such as millennials. These data provide valuable insights when trying to anticipate Spanish millennial consumer acceptance of new gluten free pulse snacks.

A review of extrusion-modified underutilized cereal flour: chemical composition, functionality, and its modulation on starchy food quality

Compared with three major cereals, underutilized cereals (UCs) are those with less use but having abundant bioactive components and better functionalities after proper processing. As a productive and energy-efficient technology, extrusion has been used for UC modification to improve its technological and nutritional quality. Extrusion could induce structural and quantitative changes in chemical components of UC flour, the degree of which is affected by extrusion intensity. Based on the predominant component (starch), functionalities of extruded underutilized cereal flour (EUCF) and potential mechanisms are reviewed. Considering bioactive compounds, it also summarizes the physiological functions of EUCF. EUCF incorporation could modulate the dough rheological behavior and starchy foods quality. Controlling extrusion intensity or incorporation level of EUCF is vital to achieve sensory-appealing and nutritious products. This paper gives comprehensive information of EUCF to promote its utilization in novel staple foods.

Impact of Thermal Treatment on the Starch-Protein Interplay in Red Lentils: Connecting Molecular Features and Rheological Properties

Thermal treatments are widely applied to gluten-free (GF) flours to change their functionality. Despite the interest in using pulses in GF formulations, the effects of thermal treatment at the molecular level and their relationship with dough rheology have not been fully addressed. Raw and heat-treated red lentils were tested for starch and protein features. Interactions with water were assessed by thermogravimetric analysis and water-holding capacity. Finally, mixing properties were investigated. The thermal treatment of red lentils induced a structural modification of both starch and proteins. In the case of starch, such changes consequently affected the kinetics of gelatinization. Flour treatment increased the temperature required for gelatinization, and led to an increased viscosity during both gelatinization and retrogradation. Regarding proteins, heat treatment promoted the formation of aggregates, mainly stabilized by hydrophobic interactions between (partially) unfolded proteins. Overall, the structural modifications of starch and proteins enhanced the hydration properties of the dough, resulting in increased consistency during mixing.

Recent Progress on Improving the Quality of Bran-Enriched Extruded Snacks

The incorporation of milling by-products, in particular bran, into starch-based extruded snacks allows manufacturers to address two consumer demands at once, i.e., those for goods that are more sustainably produced and of higher nutritional value. However, the higher fiber content in bran than in refined cereal flours poses a limit to the amount that can be included without compromising the quality of extruded snacks, which crucially depends on expansion. Thus, several studies have focused on the effect of bran on the physicochemical characteristics of extruded snacks, leading to the need to review the recent findings in this area. Opportunities, challenges, and potential solutions of bran-enriched snacks are addressed, and several current knowledge gaps are highlighted. Specifically, the first part of the review presents the effects of extrusion cooking on bran's compositional aspects, focusing on structural changes and product quality. After summarizing the main quality traits of extruded snacks (e.g., expansion rate, bulk density, and textural attributes), the effects of bran enrichment on the physical and sensory characteristics of the final product are discussed. Finally, bran pre-treatments as well as processing optimization are discussed as approaches to improve the quality of bran-enriched snacks.

High-amylose corn in gluten-free pasta: Strategies to deliver nutritional benefits ensuring the overall quality

High-amylose corn alone or in combination (25% and 50%) with conventional corn was used to produce gluten-free pasta. Flour pre-gelatinization in a tank (process A) or on a conveyor belt (process B) were tested. Resistant starch (RS), soluble (SPAs) and cell-wall bound phenolic acids (CWBPAs) and antioxidant capacity were significantly higher in high-amylose corn pasta. Cooked pasta from process B showed a higher SPA concentration, likely due to the lower cooking loss. The structure of pasta prepared with process B was more homogeneous, whereas it was more compact in the case of process A, as shown by a lower starch susceptibility to α-amylase hydrolysis, higher beginning of gelatinization temperature and lower water absorption. 25% HA represents a good compromise between high RS (4.2%) and good cooking behavior. At higher HA levels, process B is more suitable to obtain pasta with a better cooking quality.