Research Article Received: 24 June 2020 Revised: 23 September 2020 Accepted article published: 2 October 2020 Published online in Wiley Online Library: 20 October 2020 (wileyonlinelibrary.com) DOI 10.1002/jsfa.10842 Development and physicochemical characterization of a new grass pea (Lathyrus sativus L.) miso Rafaela Santos, * Ana Mansidão, Mariana Mota, Anabela Raymundo and Catarina Prista Abstract BACKGROUND: Western consumers interest in Eastern fermented foods has been growing, due to their nutritional and healthy properties. In this study, new sweet misos and salty misos were produced using grass pea (Lathyrus sativus L.) – traditional Por- tuguese legume from local producers – to promote its consumption and preservation. The evolution of the new misos was eval- uated in comparison to traditional miso (made from soybean), through analysis of the chemical composition, colour, texture and linear viscoelastic behaviour. RESULTS: Throughout the fermentation process, the ascorbic acid and phenolic compounds content – with important nutri- tional value – increased in all misos, mainly in misos produced using grass pea, besides, grass pea sweet miso presented the fastest evolution and darkest colour. The texture parameters (firmness and adhesiveness) of misos decreased over time: grass pea sweet miso showed the highest firmness reduction (51.63 N to 6.52 N) and soybean sweet miso the highest adhesiveness reduction (27.76 N to 3.11 N). Viscoelastic moduli also decreased, reflecting a reduction in the degree of internal structuring for all misos. However, grass pea misos presented more structured internal systems with faster maturation kinetics than soybean misos, for which stabilization started earlier. CONCLUSION: Two innovative misos were developed from grass pea. After 4 months, the texture parameters and viscoelastic moduli for grass pea misos, were similar to the control misos made from soybean, showing that grass pea can be used as a raw material to produce a sustainable miso with potentially healthy properties. © 2020 Society of Chemical Industry Keywords: miso; grass pea; chemical composition; colour; texture; linear viscoelastic behaviour INTRODUCTION In the last decade, the concern of Western consumers regarding healthy and environmentally sustainable foods 1 has contributed to an increasing interest in Eastern legume fermented foods as a source of healthy and eco-friendly nutrients. 2 Apart from the low fat and high omega-3 and omega-6 fatty acid contents, legumes present high content in proteins, dietary fibres, micronu- trients (vitamins, minerals and amino acids) and antioxidants, such as phenolic compounds, (e.g. flavonoids, phenolic acids and tannins) with human health benefits, 3,4 many of them present in highest concentrations, and/or in a more bioactive and bio- available form, after the fermentation process. 5 However, many of these fermented foods result from spontaneous fermentation processes, being traditionally produced by ancient techniques, which do not fully meet the quality standards and reproducibility demanded by modern-day consumers. Furthermore, some of these foods are poorly characterized regarding the effect of the fermentative process on their nutritional, structural and rheologi- cal properties. 6 Miso is a Japanese fermented paste consumed in soups and as seasoning or flavouring agent. 7,8 This fermented paste is usually produced using soybean, koji (rice, barley or soybean inoculated with Aspergillus oryzae), salt and water, inoculated with an old miso culture. 9,10 In addition to A. oryzae, lactic acid bacteria and yeasts are also involved. 11 In miso preparation, koji is the main source of hydrolytic enzymes (e.g. amylases, maltase, proteases and lipases), that are involved in the digestion of the main legume structural components. 11 The substrate used to produce koji defines the three main types of miso known: rice, barley and soybean. 8 Rice miso is the most popular in Japan and is generally classified as salty or sweet, based on the salt concentration (12–14% salt for salty and 5–7% salt for sweet), flavour and colour (white, light-coloured or red). 7 As an alternative to soybean, other legumes can be used to pro- duce miso and create new, diverse and locally produced * Correspondence to: R Santos, LEAF (Linking Landscape Environment Agricul- ture and Food) Research Centre, Instituto Superior de Agronomia, Universi- dade de Lisboa, Tapada da Ajuda, 1349-017, Lisbon, Portugal. E-mail: rcsantos@isa.ulisboa.pt LEAF (Linking Landscape Environment Agriculture and Food) Research Centre, Instituto Superior de Agronomia, Universidade de Lisboa, Lisbon, Portugal J Sci Food Agric 2021; 101: 2227–2234 www.soci.org © 2020 Society of Chemical Industry 2227