Food Science and Applied Biotechnology

The cereal food group contributes significant amounts of the major macronutrients and micronutrients, making it an essential part of a healthy diet. The primary food for nutrition, energy


Introduction
One of the most significant sources of dietary proteins is cereal grains, which also contribute considerable amounts of energy, protein, carbohydrates, vitamin, and a few specific micronutrients to the diets of both animals and people (Đorđević et al. 2010).Over three billion people worldwide eat rice as a basic diet, and most of them prefer polished white rice (Park et al. 2017).The third most often grown crop worldwide is rice.More than half of the world's population eats rice as their primary staple food, with Asia, Sub-Saharan Africa, and South America being its top consumers.Global rice production is anticipated to reach 515 million tonnes by the end of 2022.The rise in world production as a result is 0.23%.India still leads the world in rice exports even though Sub-Saharan Africa is the region that imports the most (Rice production by Country 2023).In comparison to other grains, rice has higher fiber, resistant starch, and a variety of proteins and lipids when it is consuming as whole (Krishnan et al. 2021).Rice's nutritional makeup varies greatly depending on both environmental factors and variety.Due to varying soil and climatic circumstances, even the same variety of rice might exhibit compositional variances.The primary components of brown rice include 0.8-2.6%fiber, 1.5-2.1% ash, and 2.4-3.9%fat.15.4% protein (N 5.95), 1520-1610 kJ.100g -1 of calories (Bhattacharya 2017).Dietary fiber, phenolic acids, flavonoids, tocopherols, minerals, vitamins, amino acids, and oryzanol are among the phytochemicals found in brown rice (Ravichanthiran et al. 2018).In addition to lowering blood pressure and preventing cancer and heart disease, these nutritional elements also have antioxidant properties (Fukushima et al. 2020).Germination is an efficient and established method for enhancing the nutritional value of grains (Jeong et al. 2019).Numerous rice dishes have been created using diverse techniques since rice is taken in a variety of ways.Some processes that are applied directly to the grain, including parboiling, annealing and quick cooking techniques for, also include certain that promote germination (do Nascimento et al. 2022).Nutritive value as well as the level of nutrients like free amino acids, vitamins, and other compounds present in grains alters due to all those treatments and also the sensory qualities (Chaijan and Panpipat 2020).The functional elements included in germinated brown rice (GBR) are regarded as good food sources of nutrition.GBR is preferred because it not only encourages healthy metabolic pathways for greater health but also cooks more effectively and with better digestibility than non-germinated brown rice (Cho and Lim 2016).Further, the germination of rice grains may alter the amounts of a number of nutrients, including sugar, vitamin B, total protein, and gammaaminobutyric acid (Fukushima et al. 2020).The germination process influences by some environmental factors such as germination time, absence or presence of light (Jeong et al. 2019).Numerous varieties of rice grains upon varying parameters show different impacts and such works studied by researchers have been listed in Table 1.During the initial 0-24 h of germination, water is absorbed quickly.When germination starts and dormancy is broken, the metabolites at the embryo undergoes significant alteration (Frank et al. 2011).There is rise in metabolite concentrations within 24-48 h.For the initial germination enzymes are required and, it was the most crucial stage for accelerating metabolic reactions and mobilizing reserves.When rice grains germinate, they include proteins relating to metabolism that are engaged in many carbohydrates metabolic processes, including glycolysis, the tricarboxylic acid cycle, gluconeogenesis, and the pentose phosphate pathway.GABA levels continuously rises for another 72-96 h in germination.Important amino acids such alanine, arginine, glycine, methionine, proline, serine, and tyrosine, among others Valine and tryptophan concentrations were higher after 72-96 h compared to 0-24 h (Kamjijam et al. 2020).A few seed reserves are digested and used to respire and generate new cell components for the growing embryo during germination, which significantly alters the biochemical, dietary, and sensory properties of the cereal seed (Chen et al. 2016).The germination condition of many rice varieties, influences on dietary and biochemical constituents, and health advantages are highlighted and explained in this paper.

Germination
Soaking the grains or seeds in water is the initial step in the germination process.Water uptake by the grain through the pores and micropyle and be deposited there as a result of interactions mostly with proteins and fibers.During the second stage, when the pericarp ruptures in the vicinity of the germ and the radicle immediately appears, the water absorption index is stabilized.During the third stage, the percentage of water absorption increases once more, and the radicle cells grow more numerously (Nelson et al. 2013).According to Fukushima et al. (2020) temperature has a significant impact on germination, the coleoptile and root appeared 2 d after soaking at 30-35℃.
There is no germination seen at 45℃, 50℃, and 55℃ but small buds started to emerge at 40℃ after steeping for 2 d, but the germ didn't extend until 10 d later.Zhang et al. (2014) studied and compared the differences in GABA production between the two-rice variety (Indica and Japonica rice), as well as the impacts of processing parameters and addition of exogenous glutamic acid or gibberellin.The greatest amount of GABA was produced by soaking in distilled water with a pH of 7.0 and germinating seeds at 35℃ for 36 h.Kim et al. (2017) conducted an experiment to germinate a seed.To start the germination process, the seed was first soaked in distilled water in a 1:5 w/v ratio at 20℃ for 3 d.The water was changed every 24 h.The soaked seeds were put in trays and allowed to germinate for two days at 37℃ with 80% relative humidity in a seed germinator.Moongngarmand and Saetung (2010) used the procedure for the germination of rough rice, for germination, 5 kg of rough rice was steeped in tap water at room temperature for 48 h to achieve a moisture content of 40±2%.Next the rice seeds were placed over double layer of cotton cloth in plastic baskets and allowed to germinate for 48 h.For germination process (Jeong et al. 2019) steeped rough rice in tap water at room temperature for three days, with the dipping water being replaced every 24 h.The soaked rough rice was allowed to germinate for 15 to 25 mm at a temperature of 37℃ and 80% relative humidity.Phytic acid content of the germinated rice flours was reduced by 75% and the starch content by 45% after 12 h of soaking and 48 hours of germination at 30℃ (Chinma et al. 2015).A detailed diagrammatical flowchart explaining the germination process is shown on Fig. 1.Histological analysis showed that the root apical meristem undergoes active differentiation after the treatment of partial drying.Liao et al. (2015) found that between 14-21 d, roughly, basal callus inhibition of root growth was released in Picea morrisonicola Hayata; freshly formed young roots extended through the callus and then emerged into the culture media, effectively enhancing the germination process.Histological evidence and the findings of the partial-drying experiment in this study showed that a shorter partial drying time (7 d) effectively activated root meristem development, and a subsequent three-week cold storage period considerably increased germination.Liao et al. (2015) stated that their findings of the partial-drying experiment showed a shorter partial drying time (7 d) effectively activated root meristem development, and a subsequent three-week cold storage period considerably increased germination.Wu et al. (2022) found out that cadmium treatment on japonica rice restricted the root length of the rice seed but it had minimal effect on the germination rate and shoot length.

Effects of germination on various characteristics of rice
Effect on nutritional value.Since, the hydrolytic enzymes become the first to be activated due to germination conditions and act in the breakdown of starch, so carbohydrates suffer the largest alterations as a result of germination and it shows decrease in carbohydrate content (McKie and McCleary 2015) Crude protein, total sugars, reducing sugar, and total free amino acid concentrations all increased significantly at germination (Moongngarm and Saetung 2010).Chinma et al. (2015) reported that it is possible that enzymatic hydrolysis of starch to monosaccharides during germination is the cause of the decreased starch level in germinated rice flours in comparison to non-germinated rice flour.After germination, the level of protein increases.Lipid breakdown, which provided energy for the biochemical and physicochemical changes that occurred during germination, may have contributed to the decrease in fat content of rice flours on germination.Reduced total soluble solids and likely dry matter loss can be used to explain why germinated rice flour has a greater ash content than non-germinated flours.
Higher protein level and a modification in protein quality following germination could be responsible for the greater ability to absorb water of germinated rice flour (Chinma et al. 2015).The metabolism of total carbohydrates, which shown a marked reduction in quantity in each case, was attributable to this increase in the total sugar content (Sibian et al. 2017) (Table 2).
Effect on mineral content.Seed germination and PA hydrolysis are both impacted differently by different temperature ranges.At greater temperature conditions (>50℃), significant PA degradation was seen (Fukushima et al. 2020).Phytic acid is one of the main barriers restricting the availability of divalent cations such Fe 2+ , Ca 2+ , Mg 2+ , and Zn + .Due to stable complexes that phytic acid (inositol hexakisphosphatephosphate) groups form with these cations, they are not bioavailable (Singh et al. 2015).Magnesium, phosphorus, and potassium quantities of flour samples were enhanced by germination, whereas calcium, iron, sodium, and zinc were not significantly impacted (Chinma et al. 2015).
Effect on bioactive compounds.The overall vitamin E content was increased by adding αtocopherol, α-tocotrienol, and germination αtocotrienol (Kim et al. 2017).According to Yodpitak et al. (2019) Vitamin E content rises throughout the germination process, and amounts might change greatly based on the variety and germination duration.In their study on the viability of getting a germinated extract of native Thai rice (Chaijan and Panpipat 2020) noted a significant rise in GABA at 35℃ in the dark, during germination from the 36-th to the 48-th h, going up from 1.5 to 55.0 mg.kg -1 , a range that did not exceed changes up until the procedure' conclusion 96 h (Jeong et al. 2019) before germination, the total polyphenol and flavonoid content was 4.11 mg GAE.g -1 and 2.14 mg CE.g -1 , respectively.After germination, these values rise to 9.82 mg GAE.g -1 and 3.85 mg CE.g - 1 .The synthesis of phenolic compounds brought on by enzyme hydrolysis during germination is greater in germinated rice (He et al. 2011;Jeong et al. 2019).DPPH and ABTS radicals scavenging activity improved from 3.75 mg TE.g -1 and 18.58 mg AE. g -1 to 6.54 mg TE.g -1 and 28.73 mg AE.g -1 after germination (Jeong et al. 2019).(Chaijan and Panpipat 2020).After 5 h of steeping, 50 h of germination, 30℃ germination temperature, and relativehumidity of 80%, the highest GABA concentration of 51.9 mg.100 g -1 was discovered and the minimum GABA level was recorded after 5 h of steeping period, 10 h germination time, at 30℃ and at relative humidity of 70% (Hussain et al. 2020).Kaur et al. (2017) studied on ten variety of rice and they found in increase in reduced ascorbate content, tannin, tocopherol, GABA content and also antioxidant activity (Table 3).
Effect on enzymatic activity.The activation time of enzyme varies based on the type of cereal, germination, and growth conditions, and also due to presence of hormones such gibberellins, which are created in the embryos of the grains and encourage the development and manufacturing of enzymes, specifically those that are involved in the digestion of carbohydrates α-amylases.High enzymatic activity permits breakdown of macromolecules, which can make them more digestible and can produce bioactive substances, increasing functional characteristics.Typically, the addition of enzymes such amylases, proteases, and xylanases modifies the elastic properties of the dough, gas retention, and smoothness of the particle (Miransari and Smith 2014).Some plant hormones like Gibberellic acid, abscisic acid, and ethylene are produces and/or releases during the germination process which serve as indicators for the stimulation and production of enzymes such amylases, lipases, and proteases (do Nascimento et al. 2022).One of most prevalent protease that works on the degradation of storage protein during the germination of seeds iscysteine protease (Szewińska et al. 2016).Amylase enzyme is generated during germination because endosperm needs to activate stored macromolecules in order to supply nutrients for the seed during germination (Kondhare et al. 2015).
The content of amylase activity is higher in germinated rice then non germinated rice (Guzmán-Ortiz et al. 2019).Increase in amylase enzyme begins at 8 h of imbibition, with a larger increase occurring after 20 h.On the other hand, brown and rough rice that germinate at 28-30℃ displayed a gradual rise in alpha-amylase activity, reaching a peak after four days of germination.In comparison to ungerminated grain and germinated rice, amylase activity increases up to 143-fold more after 24 h germination (Moongngarm et al. 2014).Guzmán-Ortiz et al. (2019) reported that longer the steeping period, higher the percentage of water absorption which in turn encourages for enhancement of amylase activity.Alpha amylase greatly increases up to 86.97 u.g -1 after steeping the rough rice cultivar RD-6 for 2 d and 48 h germination period.Amylase-induced starch hydrolysis results in the production of sugars and changes the shape of the granule.Enzymes have the ability to hydrolyze and enter granules, producing porous surfaces, erosion along the surface in the form of sponges, and degraded granules (Lu et al. 2016) (Table 4).

Comparison with other germinated cereals
It has been noticed how germination has various positive effects on rice such as improved or increased amounts of functional compounds.However, change in nutrient profile for other germinated cereals have also been tracked in Table 5 to get a more comprehensive idea on the effects of germination overall.

Future scopes and new trends
The idea of germination is to increase the overall nutritional profile of the grains and improve its cooking behavior by soaking at various temperatures.Already, a number of ways have been identified wherein the germination rate was hugely impacted.The main aim behind improving germination is to provide better nutrients to the consumers since it has been found to elevate the essential properties of the grains (wheat, cereal, brown rice, white rice).All recent research has been tabulated in the Table 6 given below.

Health benefits
In various pieces of literature, germinated rice has been found to have numerous beneficial properties (Fig. 2).Germination encourages the enzymatic alterations of carbohydrates, particularly, interactions between starch and polyphenol that may be used to manage blood sugar levels (Oliveira et al. 2022).Pramai et al. (2018) investigated the characteristics of germinated black, red, and white rice and came to the conclusion that the germinated black rice had higher content of organic acids, phenolic compounds, and amino acids.According to Karau (2014), Kovanda (2020) and González-Burgos (2021) amino acids, organic acids and phenolic compounds are beneficial for human health by contributing in hemoglobin production, improvingdisease resistance, growth promotion and treat obesity by inhibiting adipogenesis.Tian et al. ( 2004) studied and found that germinated brown rice had higher insoluble phenolic acids which includes hydroxycinnamates.Hydroxycinnamates contain antimutagenic capabilities, and this physiological activity may be important in the cancer-prevention effect of dietary fiber.(Ferguson 2003).Brown rice that has been germinated has been shown to have a variety of physiological effects, such as cardiovascular disease (CVD), antihyperlipidemia, antihypertension, and a lower risk of cancer, diabetes, and Alzheimer's disease thereby, it can be categorized as a functional food (Wu et al. 2013).

Enzyme
Treatment References Diastase The mean diastase activity of brown rice was 456 mg of maltose per 10 g after 12 h of germination and increased to 757 mg after 48 h.The average diastase activity was 543 mg maltose per 10 g when germination took place at 25℃, and it rose to 796 mg maltose per 10 g at 35℃ (Singh et al. 2018)

αamylase
The alpha amylase concentration of germinated brown rice rose from 0.17 to 21.00 U.g -1 after being treated for 96 h at 28-30℃ in comparison to unaffected brown rice (Guzmán-Ortiz et al. 2019)

Cysteine protease
Cysteine protease, which is in charge of breaking down and mobilizing storage proteins, was observed to be present in rice in greater quantities (Szewińska et al. 2016) α-

amylase and βamylase
After germination was complete, all glutinous brown rice's -amylase activity rapidly rose and steeping proceeded for another 24-48 h (Charoenthaikij et al. 2009) Proteases Rice's protease activity increased from 0 to 0.12 (U.g -1 DM) during the course of 5 d after being subjected to the germination process.(Veluppillai et al. 2009)

Diastase, Alpha Amylase, protease
After being germinated for 4 d in the dark, diastase activity grew from 0.007 to 0.061 Units.min - , -amylase activity increased from 0.004 to 0.056 Units.min - , and protease activity increased from 0.84 to 3.89 Units.min - (Van Hung et al.2020)

Food products
Germinated rice can be incorporated into various food products and pose as a potential ingredient for obtaining various health benefits.Numerous attempts have been made by researchers with successful results in incorporating germinated rice in food products.Recent relevant researches have been listed below in Table 7.

Conclusions
Notable alterations in a number of chemical compositions, bioactive substances, and amino acids occur during rice germination.It also reworks the starch digestibility and displays an increase in GABA content.All of these modifications aim to raise the rice's quality and increase its healthbenefits.It is noteworthy to mention that all these significant properties contribute in claiming germinated rice as a potential functional food.
Various researches need to be conducted in the future for a clear understanding on germination conditions to find out the best conditions for various types or cultivars.This would create a valuable opportunity for the functional food sector, and consumers would gain health advantages from using these products.Germinated sorghum (Sorghum bicolor L. Moench) had increased GABA content up to 0.336 mg.g -1 (Elbaloula et al. 2022) Germinated chickpea increased GABA content from 6.42 to 245.76 mg.100 g -1 (Ferreira et al. 2019) Germinated soybeans were found to have a 10-fold increase compared to non-germinated soybeans from 0.216 mg.ml -1 and 0.302 mg.ml -1 to 1.343 mg.ml -1 and 1.506 mg.ml -1 respectively (Shabbir et al. 2022) Germinated barley showed an increase in GABA content from 6 mg.100 g -1 to an overall content of 11.9 mg.100 g Adlay seed (Coixlachryma-jobi L.) when germinated for 4.5 d increased p-coumaric acid (soluble free phenolic content) content from 3.11 µg.g -1 to 63.86 µg.g -1 (Xu et al. 2017).Black soybean (Glycine max L.) when germinated for 4 d showed a decrease in p-coumaric acid content from 2.96 µg.g -1 to 0.39 µg.g -1 (Kim et al. 2016).Buckwheat (Fagopyrum esculentum Moench) when germinated for 3 d the p-coumaric acid content increased from 1.74 µg.g -1 to 6.13 µg.g -1 (Zhang et al. 2015).Flaxseed (Linum usitatissimum L.) underwent germination for 10 days and had an optimum pcoumaric content of 4.33 mg.100 g -1 from an initial 0.26 mg.100 g -1 (Wang et al. 2015).Quinoa seeds (Chenopodium quinoa Willd.)germinated for 3 d and had an optimum p-coumaric acid content 1.96 mg.100 g -1 from an initial 0.09 mg.100 g -1 (Carciochi et al. 2016).

Vitamins
In sorghum (Sorghum bicolor L.), after 72 h of germination the vitamin B2 content increased (riboflavin) but showed decreased levels of vitamin E (Pinheiro et al. 2021) Germinated pea flour after undergoing germination for (24-72 h) was seen to have increased levels of vitamins B and vitamin C (Chinma et al. 2022) High performance liquid chromatography (HPLC) analysis of germinated brown rice showed the presence of vitamin E and its five isomers α-tocopherol/ tocotrienol, γ-tocopherol/ tocotrienol, and β-tocopherol, δ-tocopherol/ tocotrienol, β-tocotrienol (Kong et al. 2022)

Hydropriming
The initial seed water content of rice seeds was obtained by priming them in tap water at 30℃ for 12 h.During the early germination period, priming increased germination rate but did not enhance water intake (0-24 h after imbibition).(Matsunami et al. 2022)

Melatonin
According to the findings, the key melatonin concentration is 100μM, and the crucial interaction treatment is germination at 38ºC followed by recuperation at 26℃ for a day + 100 μM.When seeds were exposed to various high-temperature settings while being soaked in melatonin (100μM), the effect of the high temperatures on the germination rate was dramatically reduced by 18.2%, 3.2%, 3.9%, and 10.6%, respectively.(Yu et al. 2022)

Priming with rhizobacteria
According to the results, biopriming using rhizobacteria can significantly boost rice grain germination over hydropriming in just 4 d.The increase in germination is related to the improvement in amylase enzyme temperature and pH range.

Nitrogen (N) and Zinc(Zn)
When nitrogen(N) and zinc(Zn) were employed to treat the grain, the yield increased by 28.5% and 32.5%, respectively.Additionally, the largest gains of 37.9% grain were obtained with foliar application of combined N and Zn.

Infrared radiation (IR)
According to the results, it is proper to treat rice that will be used as seed grain with an IR intensity of 10.84 kW.m -2 for 7 s to obtain a temperature of 60℃; lesser IR intensities seem more appropriate.(Hampton et al. 2022)

Salicylic acid (SA)
Treatment with 0.1 mM SA significantly reduced amylase activity inhibition and accelerated the conversion of starch to soluble sugars.(Liu et al. 2022)

Pulsed light
After being exposed to pulsed light for 18 h, the glutamic acid concentration peaked, and the GABA content peaked after 24 h.Additionally, increased levels of free acids were found.

Ergothioneine (ESH) extract from Aspergillus oryzae
The findings showed that when 4% of ESH was applied, total lipid was steady and that in germinated brown rice, there were higher quantities of GABA and γ -oryzanol.(Ha et al. 2022)

Calcium and Aeration treatment
The breakdown of protein increased the overall concentration of free amino acids after aeration and a calcium ion-based pretreatment.Brown rice that had been germinated and cooked showed excellent pasting qualities and thermal stability, which helped it have the right edible attributes.(Zhang et al. 2022)

Smoke induced germination
The smoke water caused an early, partial increase in seed germination rates, indicating that seeds that ingested it may use the majority of the nutrients to begin metabolic processes earlier than seeds that received other treatments.

Product Findings References
Dumplings The storage and textural quality of the glutinous rice flour-based dumplings with the appropriate germinated brown rice flour addition (5-15%) were improved, with lower water loss and cracking rates as well as greater hardness and adhesiveness.Additionally, it also increased the digestibility of the food product.(Wang et al. 2022)

Tea
The formation of free amino acids and reducing sugars during germination promoted the non-enzymatic browning reaction and the development of aroma compounds during subsequent roasting for tea preparation; additionally, the rise in total phenolic content caused by roasting boosted antioxidant properties.(Kim et al. 2021)

Cookies
In comparison to non-germinated brown rice flour, germinated brown rice flour comprised more protein, ash, dietary fiber, and fat.Inclusion of this flour to make cookies had a good overall acceptability.(Bolarinwa et al. 2019)

Yoghurt
The proximal composition of brown rice formulations was somewhat altered by fermentation, which also increased the overall number of bioactive substances (phenolic compounds and GABA), ACE-inhibitory action, consistency index, and density.The product displayed the best biological, technological, and acceptance characteristics.(Cáceres et al. 2019)

Bread
In comparison to the control, germinated brown rice bread displayed higher specific volume (4% to 10%), decreased hardness (34% to 90%), and lower starch retrogradation (66% to 90%).(Wunthunyarat et al. 2020) Rice cake Germinated black glutinous rice was used to make fermented rice cake with the probiotic yeast saccharomyces boulardii.The created product contains antioxidants like anthocyanins, flavonoids, and GABA, each not less than 30%, according to all the results of tested analysis.(Cheirsilp et al. 2023)

Cupcake
After germination for around 40 hours, the red rice flour portrayed increased phenolic acid and flavonoid content which was then utilized to prepare cupcake with an overall acceptability of 90% approximately.(Müller et al.2021)

Figure 1 .
Figure 1.Diagrammatic representation of the rice germination process (Adapted by do Nascimento et al. 2022)

Table 2 .
Effect on nutritional value during germination Increase With longer germination times, the decreasing sugar content gradually rose.It was less than 10% at the beginning of germination and could reach 25% by the end of the germination phase.This might be as a result of rice consuming sugar in numerous biochemical processes at a rate that exceeds the rate at which it is produced during germination.

Table 3 .
Changes of bioactive compounds after germination in different varieties of rice

Table 5 .
Comparison of the effects of germinations on rice and other germinated cereals (Waleed et al. 2020)0)

Table 6 .
New trends and research in the field of germination

Table 7 .
Food products made from germinated rice