Processing and quality evaluation of dry beans (Phaseolus vulgaris) in flexible pouches

Dry beans are a nutrient‐dense food with a history of processing in metal cans to improve convenience for consumers. Flexible retort pouches have been gaining popularity as a food package to replace metal cans because they are lighter in weight and require less energy to process. While there are potential benefits of using pouches for processed bean products, a pilot‐scale pouch processing protocol for beans is needed for testing to expand to wider commercial applications. To address that need, the objectives of this study were to optimize a pouch processing method for dry beans and assess the subsequent quality of pouch‐processed beans. Black and kidney bean genotypes from different field trials and production years and harvested by different threshing methods were used in this study. Pouch processing was conducted with two types of pouches at a pilot facility, and processing quality included texture, appearance, and color. Cooking time of dry seeds was assessed to understand how variety and environmentally induced differences in cooking time influence pouch processing quality. Kidney beans that required longer dry seed cooking times had firmer texture when pouch processed (r = .72, p < .01). Both genotype and production year impacted cooking time and pouch processing quality. Threshing method had a significant impact on the appearance of processed kidney beans, while it had no significant impact on the processing quality of black beans. Pouch processing requires 42% (at 245°F/118.3°C retort temperature) or 60% (at 250°F/121°C) less retort processing time compared with canning. Both foil and non‐foil pouches can be used to differentiate varieties for processing quality, but the non‐foil pouches require much less effort to seal. This study provides a detailed methodology for pouch processing and quality evaluation of dry beans and useful information for researchers and processors in future applications of using pouches as alternative packaging for processed beans.


| INTRODUCTION
Dry beans are recognized as a nutritionally rich whole food and are a good source of fiber, protein, and iron (Bouchenak & Lamri-Senhadji, 2013;Kaale et al., 2022).However, dry bean consumption is especially low in North America, Europe, and Oceania (OCED/ FAO, 2023).One of the reasons cited for low consumption is unfamiliarity and lack of knowledge on how to prepare beans (Hughes et al., 2022;Schneider, 2002).Consumers also have a preference for convenient foods that save time and effort and fit their busy lifestyles (Jackson & Viehoff, 2016).Many consumers are also willing to pay a premium for such convenience foods (Brunner et al., 2010;Swoboda & Morschett, 2001).
Ever since the invention of canned food in the early 20th century, consumers have had access to fully cooked and shelf-stable whole beans through canned bean products.However, flexible retort pouches, which, as an alternative food packaging, can provide the same shelf-stability of metal cans, have gained more popularity in recent years and are used for a variety of foods (Kontominas et al., 2021;Majumdar et al., 2017;Martinez-Ceniceros et al., 2022;Potter, 2008).One concern of the retort pouches is that most of them are not recyclable due to their multiple layered structure; however, there has been recyclable retort pouches being developed but not yet available in the North American market (Amcor, 2021).A study has found that the demand for metal cans is experiencing slow growth while significant demand growth is expected for other retort packaging including pouches and cartons (Research and Markets, 2022).
Retort pouches are a flexible multilayered laminated package that can withstand thermal processing under pressure.There are many benefits of using pouches as a convenient and consumer-friendly form of packaging processed food.They are lighter in weight, require less time and energy in thermal processing due to their thin profile, require less energy for transportation, and are easier for the consumer to open and cook (Jun et al., 2006;Potter, 2008).The reduced heat exposure during thermal processing of pouches, can reduce nutrient losses and improve the taste, color, and flavor of the product (Featherstone, 2015;Kirwan & Coles, 2011).Therefore, the development of a pouch processing method for different market classes of beans can potentially improve the product quality and accessibility while promote bean consumption.
The processing quality of whole beans is a measure of how well they withstand the thermal process and is usually evaluated by the appearance, color, and texture.There are many factors that affect processing quality of beans.The appearance, which is the first quality attribute that consumers observe, is mainly affected by the splits of the seeds and loose seed coat (White et al., 2022).Research has found that splits in processed whole beans are affected by seed size, seed coat cracks, and seed moisture content (Forney et al., 1990;Nordstrom & Sistrunk, 1979).The blanching methods and thermal processing methods also affect processing quality and can be adjusted to optimize the product quality (Davis et al., 1980;White et al., 2022).
Variation in processing quality of beans from distinct sources, genotype, or processing methods has been observed by researchers and processors (Howard et al., 2018).According to an evaluation of pouch and canned beans available to consumers at supermarkets in Michigan, USA, pouch-processed bean products on the market have inferior quality than canned products and the organic pouch processed beans have even further reduced product quality, which demands for improvement (Wang et al., 2023).Despite all the benefits of using pouches to produce processed bean products, there has been a lack of processing protocols on pilot-scale bean processing in flexible pouches.The objectives of this study were to (1) establish a research-scale pouch processing method for dry beans; (2) test this pouch processing method with organic dry beans including black and kidney beans and evaluate their processing quality; and (3) test and compare the foil pouches and nonfoil pouches using the same bean varieties.

| Dry bean seeds
Two organic field trials with black and kidney beans (including breeding lines and commercial varieties) were conducted in the growing seasons in 2018 (Akron, Michigan) and 2019 (Unionville, Michigan) on certified organic plots provided by Everbest Organics, the largest commercial organic bean producer in Michigan.The trials were planted as a randomized complete block design with three field plot replications and followed the same row spacing and management as the rest of the commercial field.The bean plants from 2018 field trial were hand harvested and threshed with a belt thresher (Almaco BT-14) at Michigan State University (MSU).The bean plants from 2019 field trial were hand harvested, and half of each field plot was threshed with a belt thresher (Almaco BT-14) and the other half was threshed with a combine thresher using a research plot combine (Hege 140).The belt threshing is a gentle process to remove seeds from pods that minimize seed coat damage, while the combine threshing is a relatively more severe process that can cause mechanical damage to seed coat.
A total of seven black bean and eight kidney bean genotypes were selected from 2018 and 2019 field trials and two of the three field replications were used for the pouch processing test with foil pouches.All genotypes were also evaluated for seed coat mechanical damage by counting the seeds with seed coat checks (SCCs) after soaking.The results were presented as SCC severity score and SCC rate.SCC severity score was calculated according to the severity of the SCC as described in a previous study (Wang & Cichy, 2023) and ranged from 1 to 5, where 1 = no seed coat damage and 5 = all seeds split.SCC rate indicated the percentage of seeds with SCC in the measured sample.
Two black bean varieties (Zorro and Zenith) and two dark red kidney bean varieties (Montcalm and Red Hawk) were collected from conventional field trials at the MSU Montcalm Research Farm (Entrican, MI) in 2022.These varieties were processed with different types of pouches and changed retort temperature and were selected to compare their processing quality with the same varieties in the 2018 and 2019 organic trials.

| Pouch processing
The pouch processing method followed the major steps in our canning protocol (Wang et al., 2022) with cans being replaced by flexible pouches and some processing details being adjusted accordingly.There were three major steps of the pouch processing (Figures 1 and   S1): (1) seeds preparation; (2) packaging and thermal processing; and (3) quality evaluation.

| Seed preparation
Seed preparation included cleaning the seeds and equilibrating seed moisture content to be in the range of 16-18%, followed by soaking and blanching of the seeds.The solid weight (moisture-free basis) of beans in each pouch was set as 90 g regardless of market class.A target sample weight was calculated based on the moisture content of the seeds: Seeds from each sample were weighed to be within ±0.5 g of the target sample weight, and the actual sample weight was recorded.
Cleaned and weighed seeds were stored in a moisture-regulated room to equilibrate moisture for a week.
The day before the pouch processing, the dark red kidney beans were soaked overnight (12 h) in tap water with 100 ppm added calcium (in the form of CaCl 2 ).On the day of pouch processing, white kidney beans were hot soaked (30 min at 125 F/51.7 C), and all kidney beans (soaked) and all black beans (unsoaked) samples were blanched in tap water with 100 ppm added calcium with varied time length according to market class (Wang et al., 2022).

| Packaging and thermal processing
The soaked and blanched samples were cooled to room temperature and filled into the pouches.Brine (tap water with 1.5% of sugar, 1.2% of salt, and 100 ppm calcium) was prepared and cooled to <45 C before adding 270 mL per pouch.
Two types of flexible retort pouches with foil and nonfoil (microwaveable) structures from Flair Packaging (Appleton, WI) were tested in this study.The pouches with foil structure have a golden color and are made of four layers of materials including polypropylene, nylon, aluminum foil, and polyester from inside to outside (Figure 2a).The pouches with nonfoil structure do not have aluminum foil layer which makes them microwaveable.The foil pouches were sealed with a specific countertop vacuum sealer (Sammic SE-310) that seals one pouch at a time, while the non-foil pouches were easier to seal with an industrial double chamber vacuum sealer (VacSmart MV 830R) that seals eight pouches at a time (Figure S1).The foil pouches were used to process the 2018 and 2019 organic trial seeds and the processing was conducted in November 2020.The nonfoil pouches were used to process the 2022 conventional black and kidney bean seeds and the processing was conducted in November 2022.Both processing were conducted at MSU Food Processing and Innovation Center, Okemos, MI.
The heating medium in the retort for the pouches was water immersion, instead of steam for metal cans.Thermocouples (Ecklund-Harrison, Fort Myers, Florida, USA) were installed in five of the pouches before filling the beans to record the internal temperature during the retort process (Figure 2b).An additional thermocouple was used as free lead which measures the temperature of the water in the retort (model Versatort, Allpax, Covington, Louisiana, USA).
The retort temperature for the foil pouches was targeted at 245 F/118.3C and the retort temperature for the nonfoil pouches was targeted at 250 F/121 C, in order to test changed temperature and its effect on retort time.For food safety consideration, the thermal process (for retort) was required to achieve equivalent of at least 6 min of sterilization at 250 F/121.1 C (Thermal Lethality Time, F 0 = 6 min) to ensure the kill of all bacteria.

| Processing quality evaluation
The pouches with cooked samples were cooled and stored at room temperature (25 ± 1 C) for at least 2 weeks for equilibration before the quality evaluation.

| HC and WDC
Hydration coefficient (HC) and washed drained coefficient (WDC) were calculated using the sample weight, soaked weight (measured after blanch), and washed drained sample weight (measured after F I G U R E 1 Flow chart of the major steps in pouch processing.pouch processing) to indicate the water uptake of beans during soaking and thermal processing, respectively: Black beans were not soaked before processing in this study; therefore, only WDC was measured for black beans.

| Sensory evaluation
The sensory evaluation was conducted by following the post-canning sensory evaluation protocol (Wang et al., 2022).A digital high-quality image was taken for each of the samples and the images were sent to a group of six trained panelists from the lab along with an Excel sheet of the rating form and rating scale.The training and practice video for the sensory evaluation can be found in the supplemental materials in our previously published canning method (Wang et al., 2022).Basically, the kidney bean samples were rated for appearance with a scale of 1-5 (in which 1 = unacceptable and 5 = excellent), and black beans were rated for appearance plus color with a scale of 1-5 (in which 1 = light brown and 5 = dark black).

| Instrumental texture
Bean samples were fully drained before texture analysis.The TA.
XTPlus texture analyzer (Texture Technologies Corp., Hamilton, Massachusetts, USA) was used to measure the sample texture.Texture +b, yellowness]).These values were then used to compute Chroma and Hue angle using following equations (Little, 1975):

| Cooking time of dry beans
The belt-threshed dry seeds of all genotypes from 2018 and 2019 organic trials were cooked with Mattson cookers (Wang & Daun, 2005) to measure their cooking time.Seeds were stored at room temperature until they were cooked in January 2020.Two weeks prior to cooking, seeds were equilibrated for moisture content in a cold room (4 C, 75% relative humidity) to achieve 10-14% moisture content.For each genotype, a total of 30 seeds were soaked for each replicate for 12 h in distilled water and 25 seeds were used to

| Statistical analysis
The organic black bean and kidney bean data were analyzed separately.Two data sets were generated for black bean data and kidney 3.2 | Quality traits evaluation of foil pouch processed organic beans 3.2.1 | Quality traits of processed organic black beans The ANOVA results indicated that genotype and year both contributed to the variation in water uptake, processing quality, and cooking time (determined with the Mattson cooker) of tested black bean samples (Table 1a).The threshing method (normal combine threshing compared with more gentle belt threshing) did not have a significant impact on processing quality nor the SCC severity of the tested black beans (Table 1b).The effect of threshing method on dry bean cooking time was not measured in this study.
The pouch processed quality traits including WDC, texture, appearance, and color scores, and dry bean traits including SCC severity score and SCC rate and dry bean cooking time data of each genotype of the organic black beans were listed in Table 2.It was found that the aged seeds (from 2018 trial) were firmer in texture than the relatively fresher seeds (from 2019 trial) with an average of 105.1 and 88.6 kgf, respectively.According to the water uptake (WDC) data, fresher seeds absorbed more water than aged seeds during the retort process, which contributed to the softer texture of the samples.The genotype Zenith had the softest texture after pouch processing in both aged and fresh samples, while the breeding line B17220 had firmest texture among aged samples and both B17220 and Zorro were the firmest in fresh samples.Meanwhile, the cooking time of aged seeds was longer than the fresher seeds that the aged seeds took an average of 46 min to cook and the fresher seeds took an average of 32 min to cook.Among the fresh samples, B17220 had the fastest cooking time (27.3 min) and B16501 had the longest cooking time (38 min).Among the aged samples, Zorro had the shortest cooking time (39.6 min) and BL1402-15 had the longest cooking time (54.9 min).The fastest cooking time of the aged samples was longer than the longest cooking time of the fresh samples (Table 2).Previous studies reported that the environment can have a significant effect on the cooking time of dry beans (Chu et al., 2020;Marbach & Mayer, 1974).Besides the year-to-year growing environment differences, the longer storage time of 2018 aged samples could also affect the water absorbance and cooking time of those samples.The storage time and conditions are known to affect the cooking time, and the hard-to-cook phenomenon in beans happens under unfavorable storage conditions (Coelho et al., 2007;Jackson & Varriano-Marston, 1981;Reyes-Moreno et al., 1993).In this study, the seeds were stored in a cool and low-humidity environment, but some changes still happened in the seeds and led to changes in the chemical components of seeds that resulted in longer cooking time.One of the advantages of pouch processing is the shorter required processing time; thus, the aged seeds that require longer cooking time and resulted in their texture being too hard in pouch products were not suitable for pouch processing.
The pouch-processed appearance and color scores of aged samples were higher than fresher seeds, which indicated the samples with firmer texture tended to have higher sensory quality scores.However, the texture of the aged seeds was too firm, and even though they had a favorable appearance, the firmer texture would not have a favorable mouthfeel based on other studies where consumers evaluated cooked beans for taste and texture (Mkanda et al., 2007).The breeding line BL16501 had the highest appearance score with both fresh and aged seeds, and also had a good color score (>4.0) and a median texture, which could be a good candidate for improved product quality in pouch-processed black beans.
T A B L E 1 ANOVA results of organic black bean samples indicating the impact of genotype, year, and the interaction (a) and the impact of genotype, threshing method (Trt), and the interaction (b) on washed drained coefficient (WDC), pouch processing quality (texture, sensory appearance and color scores, hue angle, and chroma), seed coat check (SCC) severity in dry beans after harvest, and dry bean cooking time with a Mattson cooker (belt-threshed samples only).T A B L E 2 Pouch processing quality traits including washed drained coefficient (WDC), texture, and appearance and color scores and dry bean traits including seed coat check (SCC) severity and SCC rate and cooking time of each genotype of the tested organic black beans from two years and two harvest threshing methods.Threshing methods: Belt threshing is a gentle method, whereas combine threshing is more likely to induce damage to the seed coat.b Least significant difference (LSD) was calculated separately for the data set of belt-threshed samples from two years and the data set of belt-threshed versus combine-threshed samples in 2019 only.
T A B L E 3 ANOVA results of organic kidney bean samples indicating the impact of genotype, year, and their interaction (a) and the impact of genotype, threshing method (Trt), and their interaction (b) on hydration coefficient (HC) and washed drained coefficient (WDC), pouch processing quality (texture, appearance, hue angle, and chroma), seed coat check (SCC) severity in dry beans after harvest, and dry bean cooking time with a Mattson cooker (belt-threshed samples only).

| Quality traits of processed organic kidney beans
The ANOVA results of kidney bean samples (Table 3) indicated that genotype and year both had significant effect on water uptake during soaking (HC), processing quality (texture, appearance, hue angle, and chroma), and cooking time.The water uptake during thermal processing (WDC) was only affected by genotype.Unlike black beans, the water uptake (during soaking), the processing quality (texture and appearance score), and SCC severity of kidney beans were significantly affected by the threshing method.The kidney bean seeds were more vulnerable to seed coat damage caused by threshing during harvest and the seeds with more SCCs tended to absorb more water during soaking and tended to have more splits in processed products.
Like the black bean samples, aged kidney bean samples (from 2018 trial) had firmer texture than fresh samples (from 2019 trail), and the aged kidney beans absorbed less water than their fresh samples during soaking (Table 4).With the aged seeds, the breeding line K16957 had softest texture (93.3 kgf), and Red Hawk and Snowdon had the firmest texture (123.4 and 118.3 kgf, respectively).However, Snowdon had the softest texture under both belt and combine threshing methods with the fresh seeds, which indicated that aging had a strong effect on Snowdon in terms of texture.Like the black beans, texture of the aged kidney beans was too firm that would not be acceptable.Thus, the aged kidney beans are also not suitable for pouch processing.The cooking time of the aged samples (average of 44.2 min) as determined by the Mattson cooker were also significantly longer than the fresh samples (average of 37.2 min).Beluga had the T A B L E 4 Pouch processing quality traits including hydration coefficient (HC), washed drained coefficient (WDC), texture, and appearance scores and dry bean traits including seed coat check (SCC) severity score and SCC rate and cooking time of each genotype of the tested organic kidney beans from two years and two harvest threshing methods.

| Correlation of the quality traits
The correlations of all measured quality traits were explored and pre-  determined cooking time (r = .55,p < .05),which indicated that those samples that needed longer time to cook tended to retain their black color better during the pouch process.However, as previously mentioned, the texture of the sample can be too hard if their cooking time was too long and there were therefore not fully cooked in the pouch, which is not preferred.
In kidney beans, a significant positive correlation was identified between Mattson cooker determined cooking time and pouchprocessed texture (r = .72)(Figure 4b).Thus, the genotypes with long cooking time are not preferred for kidney bean pouch processing to avoid a too firm texture.In general, genotypes with moderate cooking time are preferred for pouch processing so that to achieve appropriate texture of the processed samples as well as a good color retention in the case of black beans.

| Quality traits of samples processed with nonfoil pouches
Two black bean varieties and two dark red kidney bean varieties grown in 2022 (fresh samples) were processed with non-foil pouches (Table 5).The results were compared with the quality traits (average of belt-threshed and combine-threshed samples) of the same varieties from 2019 samples that were processed with the foil pouches.The processing methods for foil and non-foil pouches were basically the same with the retort temperature being changed (245 F/118.3C vs. 250 F/121 C) and the retort time was different (11 vs. 7.5 min).
The quality trait results of non-foil pouch processed samples showed the same trend as the foil pouch processed samples.For example, Zorro had firmer texture than Zenith in both foil and non-foil pouches (Table 5).Red Hawk had better appearance score than Montcalm in both foil and non-foil pouches (Table 5).Therefore, the pouch processing method used for the foil pouches could be applied to non-foil pouches and to get reliable processing quality results.With shorter processing time, the black beans in non-foil pouch retained the black color better.The less required processing time of nonfoil pouches under slightly higher processing temperature also helped to save energy input.

| CONCLUSIONS
This study identified genotypic variation in pouch processing quality of organic black and kidney beans.Genotype had a significant effect on all processing quality traits; thus, the selection of appropriate bean genotype is important for achieving optimum processing quality.The year-to-year difference was also significant in both black beans and kidney beans for processing quality and cooking time.In general, fresher seeds and genotypes with moderate cooking time are more suitable for pouch processing to achieve more ideal processing quality.Aged beans or beans with longer cooking times tended to be too firm in the pouch processing conditions.The threshing methods did not have significant effect in the processing quality of black beans but had some effect on kidney beans.The kidney beans were more susceptible than the black beans to mechanical seed coat damage that occurred with combine threshing.But there was no correlation between mechanical seed coat damage incidence and pouch processing appearance.
The pouch processing method for dry beans in this study is innovative and it can be applied to both foil pouches and nonfoil pouches to successfully differentiate varieties for processing quality.The measurements were expressed in units of kilogram force (kgf) to cut through reference weight of 100 g beans.The 10-blades Kramer shear cell was used with a speed of 20 mm/s.A single texture measurement was taken for each replicate of the samples.2.3.4 | Hunter colorDrained bean sample color was measured using a Hunter Labscan XE colorimeter (Hunter Associates Laboratory Inc., Reston, Virginia, USA).Color coordinates L*, a*, and b* values were recorded (L* [0, black; 100, white], a* [Àa, greenness; +a, redness], and b* [À b, blueness; Graphical illustration of the layers and materials of the flexible pouch used in this study (a) and the pouch with thermocouple sensor attached (b).cook in boiling distilled water.Two replicates of each genotype were cooked and the average of the two replicates was used as the cooking time of the genotype in each year.Cooking time was recorded on the Mattson cooker as the time it took for 80% of the pins to drop.
bean: (1) belt-threshed samples only with 2 years of data and (2) beltthreshed versus combine-threshed samples with 1 year data.Analysis of variance (ANOVA) was conducted for each data set to test the statistical significance of variations caused by genotype, year, or threshing methods.The statistical analysis was performed using R software with "lme4" package for linear mixed-effects models, package "agricolae" was used to calculate least significant differences (LSD), and the Pearson correlation analysis of quality traits was performed and plotted in R with "corrplot" package (R Core Team, 2020).Statistical models were established with genotype, year, and threshing methods being fixed effect factors and replicates being the random effect factor.3 | RESULTS AND DISCUSSION3.1 | Time and temperature of retort/thermal processThe time-temperature plot of the foil pouches (Figure3a) showed that the retort water temperature reached the targeted temperature (245 F/118.3C) at about 41 min.At about 52 min, the exposure time for sterilization (F 0 ) of the slowest one among the five measured pouches reached 6 min, which is a typical food safety requirement used for processed beans.Therefore, the minimum cooking time for pouch processed beans with target processing temperature of 245 F/118.3C to achieve the F 0 = 6 was 11 min.The time-temperature plot of the non-foil pouches (Figure 3b) indicated that the retort water temperature reached the targeted temperature (250 F/121 C) at about 45 min and the system started the F I G U R E 3 The time-temperature and F 0 value during the water immersion retort process for the foil pouches (a) and nonfoil pouches (b).The blue line indicates the temperature of the pouch that had slowest temperature increase among the five tested pouches.cooling process at 52.5 min.Therefore, the cooking time for the nonfoil pouches with a target processing temperature of 250 F/121 C was 7.5 min.
SCC severity score and SCC rate were combined in one column because they had the same significance levels.a None of the effects were significant for SCC severity score or SCC rate.*p < .05,**p < .01,and ***p < .001,not significant.
shortest cooking time (37.5 min) and Red Hawk had the longest cooking time (55.3 min) among aged samples.Among fresh samples, Beluga, K16136, K16957, Red Cedar, and Snowdon were not different in cooking time and had the shortest cooking time, while Red Hawk still had the longest cooking time (41.6 min).The belt-threshed samples of kidney beans generally had higher appearance scores than combine-threshed samples.One outlier was the white kidney bean "Snowdon" which had lower appearance score in the belt-threshed samples, but the appearance score of both beltthreshed and combine-threshed "Snowdon" samples were toward the lower end of the range (being 1.5 and 2.4, respectively) which indicated an unacceptable and poor processing quality.Red Hawk had the highest appearance score in belt-threshed samples in both years, but K16136 had the highest appearance score among the combinethreshed samples.Unlike the black beans, in which the seed coat damage was not significantly affected by threshing method, the kidney beans had significantly higher SCC scores and SCC rate when the seeds were harvested through the combine which induced more mechanical seed coat damage.The seed coat damage induced during combine harvest resulted in more splitting seeds in the thermal processed products, which led to lower sensory appearance score of the pouch processed product.
sented in Figure 4. Texture of the pouch processed samples was positively correlated with sensory appearance score in both black beans and kidney beans.In black beans, a moderate positive correlation (r = .55,p < .01)was detected between sensory color score and appearance score.The samples with darker black color tended to be rated higher for appearance.There was also a positive correlation between pouch-processed bean color and Mattson cooker F I G U R E 4 Correlations among the quality traits of tested organic black beans (a) and kidney beans (b).R values are listed in the tables with significance of the correlation being indicated (significant levels: *p < .05,**p < .01,***p < .001).SCC, seed coat check.T A B L E 5 Comparison of the quality traits of foil pouch processed and nonfoil (microwaveable) pouch processed black beans (texture, sensory appearance score, and color score) and dark red kidney beans (texture and sensory appearance score).
pouches require less processing time and are easier to open and to pour the contents out as compared with cans.Even though this pouch processing protocol worked for both the foil and non-foil pouches, the aluminum layer of the foil pouches makes them harder to seal and made the preparation of the pouches before retorting very timeconsuming.The use of non-foil pouches significantly reduced the sealing time.The retort temperature of 250 F/121.1 C instead of 245 F/118.3C shortened the processing time and can potentially reduce energy cost and elevate the bean product quality especially for black beans.AUTHOR CONTRIBUTIONS Weijia Wang: Formal analysis; investigation; writing-original draft.Muhammad Siddiq: Conceptualization; writing-review and editing.Kirk Dolan: Conceptualization; funding acquisition; supervision; writing-review and editing.Karen Cichy: Conceptualization; funding acquisition; writing-review and editing.
Belt threshing is a gentle method, whereas combine threshing is more likely to induce damage to the seed coat.
a Threshing methods: b Least significant difference (LSD) was calculated separately for the data set of belt-threshed samples from two years and the data set of belt-threshed versus combine-threshed samples in 2019 only.