Effect of Cold Storage and Reheating of Parboiled Rice on Postprandial Glycaemic Response, Satiety, Palatability and Chewed Particle Size Distribution

Factors associated with eating rate: a systematic review and narrative synthesis informed by socio-ecological model

Accumulating evidence shows associations between rapid eating and overweight. Modifying eating rate might be a potential weight management strategy without imposing additional dietary restrictions. A comprehensive understanding of factors associated with eating speed will help with designing effective interventions. The aim of this review was to synthesise the current state of knowledge on the factors associated with eating rate. The socio-ecological model (SEM) was utilised to scaffold the identified factors. A comprehensive literature search of eleven databases was conducted to identify factors associated with eating rate. The 104 studies that met the inclusion criteria were heterogeneous in design and methods of eating rate measurement. We identified thirty-nine factors that were independently linked to eating speed and mapped them onto the individual, social and environmental levels of the SEM. The majority of the reported factors pertained to the individual characteristics (n = 20) including demographics, cognitive/psychological factors and habitual food oral processing behaviours. Social factors (n = 11) included eating companions, social and cultural norms, and family structure. Environmental factors (n = 8) included food texture and presentation, methods of consumption or background sounds. Measures of body weight, food form and characteristics, food oral processing behaviours and gender, age and ethnicity were the most researched and consistent factors associated with eating rate. A number of other novel and underresearched factors emerged, but these require replication and further research. We highlight directions for further research in this space and potential evidence-based candidates for interventions targeting eating rate.

Influence of instant rice characteristics and processing conditions on starch digestibility-A review

Instant rice is increasingly popular around the world due to its convenience, but it commonly has a high glycemic index, and a frequent consumption might contribute to the occurrence of many chronic diseases. In this review, the main factors determining starch digestibility of instant rice were comprehensively evaluated, aiming to help the rice industry develop instant rice with slow starch digestibility. Starch digestibility in instant rice can be reduced by manipulating its intrinsic and extrinsic nutrients. Processing conditions, including pre-gelatinization, storage, and reheating are also important for the starch digestibility of instant rice. Individual differences in terms of glycemic response to the same carbohydrate-based diet should be considered when knowledge is transformed from in vitro method to human conditions. This review contains important information that has the potential to reduce the starch digestibility of instant rice and improve public health.

The influence of dough kneading time and flour particle size distribution on white bread structure, glycemic response and aspects of appetite

BACKGROUND & AIMS

White bread is widely consumed in many countries despite being a high-glycemic index (GI) food. It has been shown that the "food matrix effect" may help with diabetes and obesity management through lowering GI and appetite. This study aimed at investigating the effects of dough kneading time and flour particle size on white bread structure, glycemic response, and aspects of appetite.

METHODS

A two-phase randomized cross-over design was used in 10 healthy subjects over the course of 2 h. In phase 1, Texture Profile Analysis (TPA) attributes, Scanning Electron Microscope (SEM) image, glycemic response, and appetite aspects of white bread made with a 15-min dough kneading time (K15) were compared with white bread made with a 10-min dough kneading time (K10). In phase 2, TPA, SEM image, glycemic response, and satiety score of white bread made with coarse flour (CF) were compared to white bread made with fine flour (FF).

RESULT

With increasing hardness (force required to compress a food between the molars to a given deformation), total blood glucose IAUC in K15 (IAUC = 119 ± 12; GI = 66) was significantly (p < 0.05) lower than in K10 (IAUC = 154 ± 10; GI = 81). No marked difference was observed between K15 and K10 on aspects of appetite except for hunger. There was no significant (p > 0.05) difference in glycemic response between CF (IAUC = 126 ± 18; GI = 64) and FF (IAUC = 147 ± 12; GI = 81). Similarly, no discernible difference in satiety between CF and FF.

CONCLUSION

Changes in processing conditions can improve blood glucose response relalated to white bread consumption.

Influence of Some Spaghetti Processing Variables on Technological Attributes and the In Vitro Digestion of Starch

Durum semolina spaghetti is known to have a low-moderate glycaemic index but the impact of various processing variables during the manufacture and cooking of pasta does affect pasta structure and potentially could alter starch digestion. In this study, several process variables were investigated to see if they can impact the in vitro starch digestion in spaghetti while also monitoring the pasta’s technological quality. Cooking time had a large impact on pasta starch digestion and reducing cooking from fully cooked to al dente and using pasta of very high protein content (17%), reduced starch digestion extent. The semolina particle size distribution used to prepare pasta impacted pasta quality and starch digestion to a small extent indicating a finer semolina particle size (<180 µm) may promote a more compact structure and help to reduce starch digestion. The addition of a structural enzyme, Transglutaminase in the pasta formulae improved overcooking tolerance in low protein pasta comparable to high protein pasta with no other significant effects and had no effect on starch digestion over a wide protein range (8.6−17%). While cold storage of cooked pasta was expected to increase retrograded starch, the increase in resistant starch was minor (37%) with no consequent improvement in the extent of starch digestion. Varying three extrusion parameters (die temperature, die pressure, extrusion speed) impacted pasta technological quality but not the extent of starch digestion. Results suggest the potential to subtly manipulate the starch digestion of pasta through some processing procedures.

Culinary strategies to manage glycemic response in people with type 2 diabetes: A narrative review

Diet plays a critical role in the management of many chronic diseases. It is well known that individuals with type 2 diabetes (T2D) need to pay close attention to foods rich in carbohydrates to better manage their blood sugar. Usually, individuals are told to increase their dietary fiber intake which is associated with better glycemic control and limit their overall carbohydrate consumption. However, there are many other cooking strategies available to reduce the glycemic response to meals rich in carbohydrates and with a high glycemic index, such as adding fats, proteins, or vinegar, modifying the cooking or preparation processes, and even the selection and storage of foods consumed. The aim of the present narrative review is to summarize some of these existing strategies applied to the cooking process and their ability to modulate glycemic response to meals in individuals with T2D.

The Impact of Innovative Plant Sources (Cordia myxa L. Fruit (Assyrian Plum) and Phoenix dactylifera L. Biowaste (Date Pit)) on the Physicochemical, Microstructural, Nutritional, and Sensorial Properties of Gluten-Free Biscuits

The gluten-free products available on the markets are deficient in bioactive compounds and high in cost. The present study is designed to develop gluten-free biscuits with enhanced nutritional properties. The gluten-free biscuits are formulated with rice flour (RF) incorporated with Assyrian plum fruit flour (APF) and bio-waste date-pit flour (DPF) according to the following ratios; RF:DPF:APF (100:0:0)/T0, (90:5:5)/T1, (80:10:10)/T2, and (70:15:15)/T3. The results demonstrate that flour blends with different concentrations of APF and DPF incorporated in RF have high contents of protein, damaged starch, crude fiber, ash, phytochemicals, and antioxidants in contrast to 100% RF, which shows the lowest values for all these parameters. The pasting properties of the flour blends reveals that the values of peak, final, breakdown, and setback viscosities reduce from T1 to T3. Similarly, a differential scanning calorimeter reveals that the phase transition temperature of the flour blends decreases with the increasing amylose content. Moreover, the scanning electron microscopy of the biscuit samples shows a positive contribution of APF and DPF for the development of the desired compactness of the structure due to the leaching of amylose content from the starch. The total phenol content (TPC) and total flavonoid content (TFC) increase from 38.43 to 132.20 mg GAE/100 g DW and 18.67 to 87.27 mg CE/100 g DW, respectively. Similarly, the antioxidant activities of biscuits improved. The protein and fiber contents of the biscuits increased from 10.20 to 14.73% and 0.69 to 12.25%, respectively. The biscuits prepared from T3 resulted in a firmer texture with a reduced spread ratio. However, the formulation of T1 and T2 biscuit samples contributed to desirable physical and sensory properties. Therefore, the addition of DPF and APF to RF is a sustainable way to make gluten-free biscuits as they provide adequate amylose, damaged starch, and fiber content to overcome the essential role of gluten in the baked product with nutraceutical properties.

Impact of Low-Temperature Storage on the Microstructure, Digestibility, and Absorption Capacity of Cooked Rice

This study examined the effects of low-temperature storage on the microstructural, absorptive, and digestive properties of cooked rice. Cooked rice was refrigerated and stored at 4 °C for 0.5, 1, 3, 5, and 7 days, as well as frozen and preserved at −20, −40, and −80 °C for 0.5, 1, 3, 5, 7, 14, 21, and 28 days. The results indicated that the stored rice samples generally exhibited a higher absorption capacity for oil, cholesterol, and glucose than the freshly cooked rice. In addition, after storage, the digestibility of the cooked rice declined, namely, the rapidly digestible starch (RDS) content and estimated glycemic index (eGI) decreased, whereas the slowly digestible starch (SDS) and resistant starch (RS) content increased. Moreover, the increment of the storage temperatures or the extension of storage periods led to a lower amylolysis efficiency. Scanning electron microscopy (SEM) analysis indicated that storage temperature and duration could effectively modify the micromorphology of the stored rice samples and their digestion. Moreover, microstructural differences after storage and during simulated intestinal digestion could be correlated to the variations in the absorption capacity and digestibility. The findings from this study will be useful in providing alternative storage procedures to prepare rice products with improved nutritional qualities and functional properties.

Influence of resistant starch resulting from the cooling of rice on postprandial glycemia in type 1 diabetes

Introduction

Carbohydrates are one of the macronutrients which have the most substantial influence on glycemic response. The cooling of rice after cooking causes retrogradation of starch, which becomes a non-absorbable product in the human digestive tract.

Aim of the study

This study aimed to assess whether cooling of rice affects postprandial glycemia in subjects with type 1 diabetes.

Materials and methods

The study included 32 patients with type 1 diabetes. Each participant of the study consumed two standardized test meals consisting of long-grain white rice. One of the test meals was served immediately after preparation, and another was cooled for 24 h at 4 °C after preparation and reheated before being served. Postprandial glycemia was measured for 3 h using the FreeStyle Libre flash glucose monitoring system for each patient.

Results

After consumption of the test meal containing rice subjected to the cooling process when compared to fresh rice, a significantly lower value of maximum glycemia (11 vs. 9.9 mmol/L, p = 0.0056), maximum glycemic increase (2.7 vs. 3.9 mmol/L, p < 0.0001), areas under the glycemic curve (135 vs. 336 mmol/L * 180 min, p < 0.0001) and significantly shorter time to peak (35 vs. 45 min, p = 0.031) was observed. There was a significantly higher number of hypoglycemic episodes among the patients after consuming test meals with cooled rice compared to fresh ones during 180 min of observation (12(38) vs. 3(9), p = 0.0039).

Conclusions

Consumption of rice subjected to the cooling process results in a lower increase of postprandial blood glucose in subjects with type 1 diabetes. At the same time it increases the risk of postprandial hypoglycemia using a standard insulin dose.

Microwave reheating enriches resistant starch in cold-chain cooked rice: A view of structural alterations during digestion

Cold-chain cooked rice is an instant food consumed worldwide. Through inspecting rice structural alterations during digestion, this work discloses how microwave reheating tailors the starch digestibility of cooked rice following cold storage. The cold storage allowed approximately 2% of B-type (not V-type) starch crystallites, more nanoscale and short-range orders, and smaller pores in the rice matrix. These changes retarded the hydrolysis of structural domains (e.g., amorphous regions and short-range orders) during digestion, which increased the content of slowly digestible starch to about 38.16%. Then, microwave reheating partially disrupted the B-type crystallites and nanoscale orders, but unaffected the contents of V-type crystallites and short-range orders. Even with such structural disruptions, the resistant starch content was apparently increased to approximately 30.06%, as the structural domains became less susceptible to the digestion. Additionally, for the rice samples, the percentage of V-type crystallites could be largely increased from ca. 3% to 13%-14% during digestion.

Cold-chain cooked rice with different water contents: Retarded starch digestion by refrigeration

Cold-chain cooked rice is a widely-consumed instant food. While the quality of cooked rice as affected by processing has been widely studied, it remains largely unexplored how concurrent cold-chain conditions (e.g., refrigeration time with specific water contents) tailor the structure and starch digestibility of cooked rice. Here, as shown by combined techniques (e.g., scanning electron microscopy and small angle X-ray scattering), the cold storage (1 to 3 days) of cooked rice at 1.1:1 w/w water-to-rice ratio increased the uniformity of the rice matrix, strengthened the nonperiodic structure, and allowed more B-type starch crystallites and short-range orders. This induced an increase in the slowly digestible starch (SDS) content (from ca. 33.7% to 38.5%) as the refrigeration time rose. In contrast, for cooked rice with 1.5:1 w/w water-to-rice ratio, the cold storage (mainly 1 day) strengthened the matrix uniformity and the nonperiodic structure, and eventually increased the resistant starch (RS) content from ca. 10.3% to 17.7%. The present data could facilitate the design of cold-chain cooked rice with tailored starch digestibility.

'Old Is Gold': How Traditional Indian Dietary Practices Can Support Pediatric Diabetes Management

Nutrition is crucial for maintaining normal growth, development, and glycemic control in young people with diabetes (PwD). Undue restrictions cause nutrient deficiencies as well as poor adherence to meal plans. Widespread availability of low-cost, ultra-processed, and hyperpalatable food is further damaging. Most families struggle to find ways to provide nutritious, yet attractive, food with a low glycemic index (GI). India is one of the oldest continuous civilizations with a rich and diverse cultural and culinary heritage. Traditional dietary practices, including the centuries-old 'Thali' (meaning plate) concept, emphasize combinations (grains, lentils, vegetables, dairy, spices, prebiotics and probiotics, and fats) of local, seasonal, and predominantly plant-based ingredients. These practices ensure that all of the necessary food groups are provided and fit well with current evidence-based recommendations, including the International Society for Pediatric and Adolescent Diabetes (ISPAD) 2018 Guidelines. Techniques for the preparation, cooking, and preservation of food further impact the GI and nutrient availability. These practices benefit nutrient density, diet diversity, and palatability and thus improve adherence to meal plans and glycemic control. This narrative review describes the ancient wisdom, food composition, and culinary practices from across India which are still valuable today. These may be of benefit worldwide to improve glycemic control as well as quality of life, especially in PwD.

Impact of processing techniques on the glycemic index of rice

Rice is an important starchy staple food and generally, rice varieties are known to have a higher glycemic index (GI). Over the years, the significance of GI on human health is being better understood and is known to be associated with several lifestyle disorders. Apart from the intrinsic characteristics of rice, different food processing techniques are known to have implications on the GI of rice. This work details the effect of domestic and industrial-level processing techniques on the GI of rice by providing an understanding of the resulting physicochemical changes. An attempt has been made to relate the process-dependent digestion behavior, which in turn reflects on the GI. The role of food constituents is elaborated and the various in vitro and in vivo approaches that have been used to determine the GI of foods are summarized. Considering the broader perspective, the effect of cooking methods and additives is explained. Given the significance of the cereal grain, this work concludes with the challenges and key thrust areas for future research.

Effect of cooking, 24 h cold storage, microwave reheating, and particle size on in vitro starch digestibility of dry and fresh pasta

The aim of this study was to investigate the effect of preparation method and particle size on digestion of starch in fresh and dry pasta types. Pasta samples were boiled, refrigerated and re-heated, with samples collected after each stage, and then prepared as small (2 mm) and large (5 mm) particles for subsequent starch digestibility testing and logarithm of slope analyses. There were significant main effects of particle size (F_1,24 = 568.895, p < 0.001, η_p² = 0.960) and processing treatment (F_2,24 = 19.897, p < 0.001 η_p² = 0.624) on starch digestibility overall, however the main effect of pasta type was not significant at the p < 0.05 level (F_1,24 = 2.978, p = 0.097, η_p² = 0.110). Particle size had the largest effect on digestibility, and the extent of starch digestion was at least 50% lower in samples prepared as large particles compared with small particles. The most digestible sample was the boiled fresh-type pasta prepared as small particles (C_∞ = 57.9%) and cold storage alone and/or with subsequent re-heating significantly reduced the extent of digestion in this sample to ∼40.6%. In the dry pasta type, processing treatment had no significant effects on starch digestibility. The rate constant, k, was not significantly altered by processing treatment or pasta type (k = 0.0275 min^-1, mean of all samples). These findings suggest that cold-storage and re-heating treatments have limited potential to impact on glycaemic responses and highlight the importance of masticated particle size as a potential rate-limiting factor in digestibility studies.

Reducing the glycemic impact of carbohydrates on foods and meals: Strategies for the food industry and consumers with special focus on Asia

Type 2 diabetes is increasingly prevalent in Asia, which can be attributed to a carbohydrate-rich diet, consisting of foods in the form of grains, for example, rice, or a food product made from flours or isolated starch, for example, noodles. Carbohydrates become a health issue when they are digested and absorbed rapidly (high glycemic index), and more so when they are consumed in large quantities (high glycemic load). The principal strategies of glycemic control should thus aim to reduce the amount of carbohydrate available for digestion, reduce the rate of digestion of the food, reduce the rate of glucose absorption, and increase the rate of glucose removal from blood. From a food perspective, the composition and structure of the food can be modified to reduce the amount of carbohydrates or alter starch digestibility and glucose absorption rates via using different food ingredients and processing methods. From a human perspective, eating behavior and food choices surrounding a meal can also affect glycemic response. This review therefore identifies actionable strategies and opportunities across foods and meals that can be considered by food manufacturers or consumers. They are (a) using alternative ingredients, (b) adding functional ingredients, and (c) changing processing methods and parameters for foods, and optimizing (a) eating behavior, (b) preloading or co-ingestion of other macronutrients, and (c) meal sequence and history. The effectiveness of a strategy would depend on consumer acceptance, compatibility of the strategy with an existing food product, and whether it is economically or technologically feasible. A combination of two or more strategies is recommended for greater effectiveness and flexibility.

Method of Food Preparation Influences Blood Glucose Response to a High-Carbohydrate Meal: A Randomised Cross-over Trial

The aim of this study was to establish the blood glucose response to different cooking methods of pasta. Participants consumed three identical meals in a random order that were freshly cooked (hot), cooled and reheated. Blood glucose concentrations were assessed before, and every 15 min after ingestion of each meal for 120 min. There was a significant interaction between temperature and time (F ( 8.46 - 372.34 ) = 2.75, p = 0.005), with the reheated (90 min) condition returning to baseline faster than both cold (120 min) and hot conditions. Blood glucose area under the curve (AUC) was significantly lower in the reheated (703 ± 56 mmol·L-1·min-1) than the hot condition (735 ± 77 mmol·L-1·min-1, t ( 92 ) = -3.36, pbonferroni = 0.003), with no significant difference with the cold condition (722 ± 62 mmol·L-1·min-1). To our knowledge, the current study is the first to show that reheating pasta causes changes in post-prandial glucose response, with a quicker return to fasting levels in both the reheated and cooled conditions than the hot condition. The mechanisms behind the changes in post-prandial blood glucose seen in this study are most likely related to changes in starch structure and how these changes influence glycaemic response.

The Effect of Cold Treatment of Parboiled Rice with Lowered Glycaemic Potency on Consumer Liking and Acceptability

A significant reduction in rice starch digestibility and subsequent postprandial blood glucose responses following extended cold treatment (at 4 °C for 24 h) have been demonstrated in both in vitro and in vivo studies, respectively. The impact of cold treatment was more significant for parboiled rice compared to other rice varieties. This study aimed to investigate consumer liking of sensory characteristics that may influence consumer acceptability of three available rice products in the Auckland region (medium grain white, medium grain brown and parboiled rice, which were either freshly boiled or cold-treated and reheated). The consumer liking of sensory characteristics (colour, taste, flavour, and texture) of each rice sample were accessed using visual analogue scales (VAS) in a randomized single blind setting. In the second stage, the participants evaluated their acceptability on VAS after the nutritional value and the characteristics of the rice samples were revealed. Sixty-four rice consumers reported higher likings of sensory characteristics of cold-treated parboiled rice and medium grain brown rice. The effect of cold treatment on the liking of sensory characteristics was more significant for parboiled rice (p < 0.05). Participants who are between 36 and 55 years old and consume rice domestically more than 10 times per month preferred cold-treated brown rice (73.8% of the participants' population (67.4%, 80.2%)) and parboiled rice (74.3% of the participants' population (67.9%, 80.7%)) (p < 0.001). As a result, cold-treated reheated parboiled rice received higher likings and acceptability and could be recommended and accepted as a healthier replacement of the daily staple meal.

Parboiling reduced the crystallinity and in vitro digestibility of non-waxy short grain rice

The impact of parboiling on starch digestibility of cooked rice was examined through an in vitro digestion model. Results indicated that the equilibrium starch hydrolysis of polished rice was the highest (86.55%), followed by that of parboiled-polished (83.94%), brown (80.59%) and parboiled rice (76.95%). X-ray diffraction analysis indicated that A-type crystals were predominant in brown rice and polished rice, while A-, B- and V-type crystalline structures coexisted in parboiled rice and parboiled-polished rice. Thin and compact layers were observed on the surfaces of parboiled rice and were considered to be physical barriers that reduce the starch digestibility. The study demonstrates that parboiling could change the crystallinity and reduce the starch digestion of rice significantly.